03 MacNeil COVID 508

Updates to COVID -19 Vaccine Effectiveness
COVID -19 Session
Coronavirus and Other Respiratory Viruses Division
June 25, 2025National Center for Immunization and Respiratory Diseases

2•Vaccine effectiveness methods & context
•Estimates of COVID -19 Vaccine Effectiveness in Children
•Estimates of COVID -19 Vaccine Effectiveness in Adults
•ConclusionsAgenda –COVID -19 vaccine effectiveness (VE)
Methods & Context
3
4
Case ControlPerson with acute
respiratory illness
SARS -CoV-2 test
COVID -19
vaccination status
For respiratory viruses, CDC primarily uses case -control studies, including
the test -negative design (TND), to measure vaccine effectiveness (VE)
Effectiveness = 1 – (odds ratio ) x 100%    Odds ratio = 𝑂𝑑𝑑𝑠  𝑜𝑓 𝑖𝑚𝑚𝑢𝑛𝑖𝑧𝑎𝑡𝑖𝑜𝑛 𝑐𝑎𝑠𝑒𝑠
𝑂𝑑𝑑𝑠  𝑜𝑓 𝑖𝑚𝑚𝑢𝑛𝑖𝑧𝑎𝑡𝑖𝑜𝑛 𝑐𝑜𝑛𝑡𝑟𝑜𝑙𝑠
VE findings should be interpreted as the
added benefit provided by COVID -19
vaccination in a population with a high
prevalence of vaccine - and infection -induced
immunity.
5VISION Multi -Site Network of Electronic Health Records
>300 emergency departments and urgent cares clinics and >200 hospitals
▪Design: Test-negative design
▪Population: Persons visiting a participating emergency
department or urgent care or hospitalized with COVID -
19-like illness with a SARS -CoV-2 NAAT test result
within 10 days before or 72 hours after encounter
−Cases : CLI with positive  NAAT or antigen for SARS -CoV-2
and no positive NAAT for RSV or influenza
−Controls : CLI with negative  NAAT for SARS -CoV-2 and no
positive NAAT for influenza (≥18 years) or RSV (≥60 years)
▪Vaccination data: Documented by electronic health records and state and city registries
CLI = COVID -19-like illness; ED/UC = emergency department/urgent care; RSV = respiratory syncytial virus; NAAT = nucleic acid am plification test
CLI is defined based on the presence of specific discharge diagnosis codes. Additional methods available: Link -Gelles, et al. MM WR.
https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm
6
•Case infants: hospitalized for COVID -19 as the primary reason
for admission and with a positive SARS -CoV-2 NAAT or antigen
test result
•Control infants: hospitalized for COVID -19-like illness and
negative SARS -CoV-2 NAAT result, matched to case infants by
site; hospitalized within 4 weeks of case infant admissionOvercoming COVID -19 Network
•Design: Case -control study to assess
effectiveness of maternal vaccination
against COVID -19-related hospitalizations in
infants <6 months of age
•Population: 26 pediatric hospitals in 20
states
•Data collection: Baseline demographic and
clinical characteristics obtained via chart
abstraction and parent interview
•Vaccination status: Maternal vaccination
status verified using state vaccination
registries, electronic medical records, or
other sources
6
7IVY Network —26 hospitals, 20 U.S. States
•Design : Test-negative, case -control design
•Population : Adults  ages  ≥18 years  hospitalized with COVID -19-
like illness* and SARS -CoV-2 test results within 10 days of
illness onset and 3 days of admission
–Cases: CLI and test  positive  for SARS -CoV-2 by NAAT or antigen
–Controls : CLI and test negative  for SARS -CoV-2, influenza (≥18
years) and RSV (≥60 years) by RT -PCR
•Vaccination data: Electronic medical records, state and city
registries, and plausible self -report
•Specimens: Nasal swabs  obtained on all patients for central
RT-PCR testing and whole genome sequencing
*COVID -19-like illness = CLI; CLI  is defined as presence of any one of the following: fever, cough, shortness of breath, chest imaging consistent with pneumoni a, or hypoxemia
NAAT = nucleic acid amplification test

8Measuring COVID -19 Vaccine Effectiveness (VE)
Measure Definition* Example
vaccinated
groupExample comparison group
Absolute VE Compares frequency of health outcomes in
vaccinated and unvaccinated people Received  original
monovalent doseReceived no COVID -19 vaccines ever
Relative VE Compares frequency of health outcomes in
people who received one type of vaccine to
people who received a different vaccineReceived  bivalent
doseEligible for, but did not receive,
bivalent COVID -19 vaccine , but
received original monovalent dose
VE of 2023 -2024
COVID -19 vaccinesCompares people who received 2023 -2024
COVID -19 vaccine to people who did not,
regardless of past COVID -19 vaccinationReceived
2023 -2024 doseEligible for, but did not receive, a
2023 -2024 dose , regardless of past
COVID -19 vaccination history
VE of 2024 -2025
COVID -19 vaccinesCompares people who received 2024 -2025
COVID -19 vaccine to people who did not,
regardless of past COVID -19 vaccinationReceived
2024 -2025 doseEligible for, but did not receive, a
2024 -2025 dose , regardless of past
COVID -19 vaccination history
* Prior SARS -CoV-2 infection is not generally considered, as it is documented inconsistently in medical records.
9COVID -19 Vaccination Coverage Among Children and Adolescents 6 Months -17
Years, by Season and Age Group, National Immunization Survey, 2023 -2025
Weekly estimates of COVID -19 vaccination coverage for vaccination among children through December 31, 2023, were calculated usin g data from the National Immunization Survey –Child COVID Module (NIS –
CCM) . The NIS –CCM was discontinued at the end of 2023 and questions regarding COVID -19 vaccination status and intent were added to t heNational Immunization Survey –Flu (NIS–Flu).
NIS–CCM and NIS –Flu are national random -digit dial cellular telephone surveys of households with children ages 6 months through 17 years; NIS –Flu is conducted during October -June. The respondent to a NIS –
Flu survey is a parent or guardian who said they were knowledgeable about the child's vaccination history. All estimates are based upon parental report of receipt of vaccination and month of that vaccination.
More information : https://www.cdc.gov/covidvaxview/weekly -dashboard/child -coverage -vaccination.html  0%25%50%75%100%
Sep Oct Nov Dec Jan Feb Mar AprCOVID -19 vaccine coverage (%)
Month6 months-4 years, 2023-2024
6 months-4 years, 2024-2025
5-17 years, 2023-2024
5-17 years, 2024-2025
10COVID -19 Vaccination Coverage Among Adults ≥18 Years, 2023 -2024 and
2024 -2025, NIS -ACM
National Immunization Survey -Adult COVID Module: Data from adults age ≥18 years are collected by telephone interview using a random -digit -dialed sample of cell telephone numbers  stratified by
state, the District of Columbia, five local jurisdictions (Bexar County TX, Chicago IL, Houston TX, New York City NY, and Phi ladelphia County PA), and Puerto Rico and the U.S. Virgin Islands. Data are
weighted to represent the non -institutionalized U.S. population and mitigate possible bias that can result from an incomplete sa mple frame (exclusion of households with no phone service or only
landline telephones) or non -response. All responses are self -reported. For more information about the survey, see https://www.cd c.gov/nis/about/index.html.0%25%50%75%100%
Sept Week 1
Sept Week 2
Sept Week 3
Sept Week 4
Oct Week 1
Oct Week 2
Oct Week 3
Oct Week 4
Nov Week 1
Nov Week 2
Nov Week 3
Nov Week 4
Dec Week 1
Dec Week 2
Dec Week 3
Dec Week 4
Jan Week 1
Jan Week 2
Jan Week 3
Jan Week 4
Feb Week 1
Feb Week 2
Feb Week 3
Feb Week 4
Mar Week 1
Mar Week 2
Mar Week 3
Mar Week 4
Mar Week 5
Apr Week 1
Apr Week 2
Apr Week 3
Apr Week 4
May Week 1
May Week 2
May Week 3
May Week 4
Jun Week 1
Jun Week 2
Jun Week 3
Jun Week 4
Jun Week 5
Jul Week 1
Jul Week 2
Jul Week 3
July Week 4
Aug Week 1
Aug Week 2
Aug Week 3COVID -19 Vaccination Coverage (%)
Week2023-2024 COVID-19 Vaccination Coverage 2024-2025 COVID-19 Vaccination Coverage
Medicare fee -for-service beneficiaries aged ≥65 years were more likely to receive a
2024 -2025 COVID -19 vaccine dose if they had an underlying medical condition
Fee-for-Service:  enrolled in Medicare Parts A/B (and not Part C) for 365 days prior to reporting period. Estimates are based on  data released by Medicare claims data through January 2025; data may be incomplete
after December 7, 2024, due to 6 -week reporting lag. Data on uptake by season, race, and ethnicity can be accessed at: https://www.cdc.gov/covidvaxview/weekly -dashboard/adults -65yrs -older -vaccination.html .
Data on uptake by underlying medical condition from internal, unpublished analyses.32%29%
28%
24%
0%25%50%75%100%
08/25/24 -
09/07/2409/08/24 -
09/21/2409/22/24 -
10/05/2410/06/24 -
10/19/2410/20/24 -
11/02/2411/03/24 -
11/16/2411/17/24 -
11/30/2412/01/24 -
12/14/2412/15/24 -
12/28/2412/29/24 -
01/11/2501/12/25 -
01/25/25% with ≥1 2024 -2025 COVID -19 vaccine dose
Two -week periodWeekly cumulative COVID -19 vaccination coverage, by underlying medical condition status,
Medicare fee -for-service beneficiaries aged ≥65 years, August 2024 -January 2025
Any immunocompromising condition
Any underling medical condition
Overall
No underlying medical condition
Estimates of COVID -19 Vaccine
Effectiveness in Children
12
Cumulative rates of COVID -19 hospitalizations for the 2024 –
2025 season are lower compared to 2023 -2024 season.
13020406080100120
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May JunHospitalizations per 100,000
population
Hospitalization monthCumulative Rates of COVID -19-Associated Hospitalizations among children and adolescents aged ≤17 years,
by Surveillance Season* — COVID -NET, July 2023 –May 2025
≤4 years, 2023 –2024 5–17 years, 2023 –2024
≤4 years, 2024 –2025 5–17 years, 2024 –2025
* Seasons are defined as July through June. The 2024 –2025 season shows data from July 2024 –April 2025 and is ongoing.
Data source: https://www.cdc.gov/resp -net/dashboard/
Note that rates are not adjusted for testing or limited to admissions where the respiratory infection is the likely primary r eason for admission.
14Age group | COVID -19 vaccination statusTotal
encountersSARS -CoV -2-
test -positive, N (%)Median interval since
last dose among
those vaccinated,
days (IQR) Adjusted vaccine effectiveness % (95% CI)
No updated 2023 -2024 COVID -19 vaccine dose*
9 months -4 years 43,246 1,886 (4) 367 (250 to 461) Ref
5-17 years 54,310 2,071 (4) 679 (491 to 810) Ref
≥18 years 279,733 31,167 (11) 756 (61 -189) Ref
2023 -2024 COVID -19 dose received 7 -59 days earlier
9 months -4 years 725 18 (2) 32 (20 to 46) 53 (24 to 70)
5-17 years 951 16 (2) 34 (19 to 47) 64 (41 to 78)
≥18 years 16,082 1,228 (8) 34 (21 -47) 49 (46 to 52)
2023 -2024 COVID -19 dose received 60 -299 days earlier
9 months -4 years 1,345 48 (4) 129 (91 to 178) 23 ( -4 to 43)
5-17 years 2,510 63 (3) 138 (100 to 185) 34 (14 to 49)
≥18 years 49,824 4,701 (9) 149 (100 -211) 12 (8 to 15)VE of 2023 –2024 COVID -19 vaccine  doses against emergency
department/urgent care encounters  — VISION
September 2023 – August 2024
-20 0 20 40 60 80 100
CDC, unpublished data
* Includes all individuals who did not receive a 2023 -2024 COVID -19 vaccine. For those aged ≥5 years, this includes unvaccinated  persons and persons who were vaccinated with ≥1 original
monovalent or bivalent COVID -19 doses. For those aged <5 years, both those in the referent group and those in the vaccinated gro up were required to have completed an initial series. The 2023 -
2024 dose could have been part of the initial series or in addition to the initial series.
Vaccine effectiveness was calculated by comparing the odds of COVID -19 vaccination in case -patients and control -patients using t he equation: (1 – adjusted odds ratio) x 100%. Odds
ratios were estimated by multivariable logistic regression. The odds ratio was adjusted for age, sex, race and ethnicity, cal end ar day, and geographic region.
15Age group | COVID -19 vaccination statusTotal
encountersSARS -CoV -2-
test -positive, N (%)Median interval since
last dose among
those vaccinated,
days (IQR) Adjusted vaccine effectiveness % (95% CI)
No updated 2024 -2025 COVID -19 vaccine dose*
9 months -4 years 31,060 809 (3) 392 (282 -662) Ref
5-17 years 38,870 926 (2) 972 (710 -1,116) Ref
≥18 years 200,933 12,927 (6) 1,068 (742 -1,224) Ref
2024 -2025 COVID -19 dose received 7 -179 days earlier
9 months -4 years 393 2 (1) 64 (30 -98) 79 (17 to 95)
5-17 years 2,208 22 (1) 81 (44 -122) 57 (33 to 72)
≥18 years 40,043 1,694 (4) 89 (50 -129) 34 (30 to 37)VE of 2024 -2025 COVID -19 vaccine  doses against emergency
department/urgent care encounters  — VISION
September 2024 – May 2025
-20 0 20 40 60 80 100
CDC, unpublished data
* Includes all individuals who did not receive a 2024 -2025 COVID -19 vaccine. For those aged ≥5 years, this includes unvaccinated  persons and persons who were vaccinated with ≥1 original
monovalent or bivalent COVID -19 doses. For those aged <5 years, both those in the referent group and those in the vaccinated gro up were required to have completed an initial series. The 2024 -
2025 dose could have been part of the initial series or in addition to the initial series.
Vaccine effectiveness was calculated by comparing the odds of COVID -19 vaccination in case -patients and control -patients using t he equation: (1 – adjusted odds ratio) x 100%. Odds
ratios were estimated by multivariable logistic regression. The odds ratio was adjusted for age, sex, race and ethnicity, cal end ar day, and geographic region.
Overcoming COVID -19: Effectiveness* of maternal vaccination† in
prevention of COVID -19–associated hospitalization  among infants§
March 9, 2022 – May 31, 2023
Simeone & Zambrano et al., MMWR, 2023: https://www.cdc.gov/mmwr/volumes/72/wr/mm7239a3.htm .
* VE estimates were based on odds of maternal vaccination during pregnancy in case -patients versus control patients, adjusted fo r U.S. Census Bureau region, admission date (monthly), age (in months),
sex, and race and ethnicity (non -Hispanic Black or African American, non -Hispanic White, non -Hispanic other, Hispanic or Latino of any race, or unknown). Study site was included as a repeated effect.
VE was calculated as (1 – adjusted odds ratio) x 100%.
†Maternal vaccination status was based on the last date of a COVID -19 mRNA vaccine dose: unvaccinated was defined as mothers who  had not received any vaccine dose before or during pregnancy,
and vaccinated was defined as mothers who received their last dose of a COVID -19 mRNA vaccine between the first day of pregnancy  and 14 days before delivery. Among those vaccinated during
pregnancy, mothers could have received ≥1 dose during pregnancy. Mothers could receive 1 dose of Ad.26.CoV2.S (Janssen [Johns on & Johnson]) vaccine before or during pregnancy and 1 dose of an
mRNA vaccine during pregnancy. Mothers who received only 1 dose of an mRNA vaccine were considered partially vaccinated and w ere excluded from the analysis. Mothers whose last vaccine dose
occurred before pregnancy were excluded from the analysis.
§Infants were excluded from analysis if they were born to mothers who had received their most recent dose before pregnancy, re ceived only 1 dose of an mRNA vaccine, received their most recent
vaccine dose within 14 days of delivery, received only 1 dose of a viral vector vaccine, or whose vaccination status could no t be verified or whose timing of vaccination was unknown.16Age group of infantNo. vaccinated/Total no. (%)
Interval between last vaccine dose and infant
hospitalization, days (IQR)Effectiveness of Maternal Vaccination against Infant Covid -19
Hospitalization % (95% CI) Case -patients Control patients
0-5 months 82/377 (22) 94/339 (28) 236 (185 –300) 35 (15 –51)
0-2 months 43/227 (19) 63/214 (29) 219 (152 –264) 54 (32 –68)
0 20 40 60 80 100
Vaccine Effectiveness (%)
Estimates of COVID -19 Vaccine
Effectiveness in Adults
17
Absolute VE of COVID -19 original  monovalent and bivalent doses received prior to  or during
pregnancy against COVID -19–associated emergency department/urgent care encounters
among immuno competent  pregnant women aged 18 -45 years  — VISION
June 2022 – August 2023
Vaccine effectiveness was calculated by comparing the odds of COVID -19 vaccination in case -patients and control -patients using t he equation: (1 – adjusted odds ratio) x 100%. Odds ratios were estimated by
multivariable logistic regression. The odds ratio was adjusted for a ge, ethnicity, race, underlying medical conditions, gestational age at encounter, site, Medicaid status, day of encounter, site  facility
urbanicity.
Pregnant women were classified as (1) unvaccinated (no COVID -19 vaccine doses) or (2) vaccinated with the last COVID -19 vaccine dose ≥7 days before the index date (including the original
monovalent and/or bivalent vaccines). The index date was defined as (1) the collection date of a respiratory specimen associa ted with the most recent positive or negative SARS -CoV-2 test result
before the ED/UC encounter or (2) the encounter date, if testing occurred only after the encounter. COVID -19 vaccination dates a nd vaccine types were identified by electronic medical records.
Original monovalent COVID -19 vaccines (11 December 2020 –31 August 2022) include Moderna, Pfizer -BioNTech, and Janssen (Johnson &  Johnson), and bivalent COVID -19 vaccines include Moderna
and Pfizer -BioNTech. Bivalent vaccines (1 September 2022 –10 September 2023) contain components from the SARS -CoV-2 ancestral and  Omicron BA.4/BA.5 strains.
Ciesla et al., OFID 2024, https://academic.oup.com/ofid/article/11/9/ofae481/7743292  18Vaccine Dosage PatternTotal
testsSARS -CoV-2-
test-positive,
N (%)Median interval
since last dose,
days (IQR)Adjusted VE
(95% CI)
Absolute VE
Unvaccinated (ref) 2991 403 (13) -- Ref
Most recent monovalent or bivalent dose received:
≥6 months before pregnancy 3014 365 (12) 483 (393,579) 6 (-11, 21)
<6 months before pregnancy 1203 143 (12) 267 (204, 325) 28 (11, 42)
During pregnancy 469 35 (7) 91 (45, 158) 52 (29, 67)
-20 020406080100
Vaccine Effectiveness (%)
VISION: VE of 2023 -2024  COVID -19 vaccination against COVID -19–associated
emergency department/urgent care encounters among immuno competent
women aged 18 -45 years, by pregnancy status  — VISION
September 2023 – August 2024
VE=vaccine effectiveness; CLI = COVID -19-like illness
Vaccine eff ectiveness was calculated by comparing the odds of COVID -19 vaccination in case -patients and control -patients using the equation : (1 – adjusted odds ratio) x 100%. Odds
ratios were estimated by multivariable logistic regression. The odds ratio was adju sted for: age, ethnicity, race, underlying medical conditions, gestational age at encounter, site,
Medicaid status, day of encounter, site facility urbanicity
CDC unpublished data 19Vaccine Dosage PatternTotal
testsSARS -CoV-2-
test-positive,
N (%)Median interval
since last dose,
days (IQR)Adjusted VE
(95% CI)
Pregnant at CLI encounter
No 2023 -2024 dose (ref) 5058 709 (14) 797 (648, 931) Ref
Most recent 2023 -2024 dose received 7 -179 days 229 13 (6) 77 (44, 120) 58 (24 -77)
Not pregnant at CLI encounter
No 2023 -2024 dose (ref) 76,636 8,052 (11) 794 (641, 931) Ref
Most recent 2023 -2024 dose received 7 -179 days 5,079 313 (6) 83 (45, 126) 37 (29 -44)
-20 020406080100
Vaccine Effectiveness (%)
20Characteristics of emergency department and urgent care encounters and hospitalizations
among adults aged ≥18 years with COVID -19-like illness, by COVID -19 case status and CDC
vaccine effectiveness network — VISION and IVY Networks
September 2024 –May 2025
CharacteristicVaccine effectiveness network and setting, no. (column %)
VISION
ED/UC encounters,
all adults aged ≥18 yearsVISION
hospitalizations,
all adults aged ≥65 yearsIVY
hospitalizations,
all adults aged ≥65 years
TotalCOVID -19
case -
patientsCOVID -19
control -
patients TotalCOVID -19
case -
patientsCOVID -19
control -
patients TotalCOVID -19
case -
patientsCOVID -19
control -
patients
Total 240,976 14,621 226,355 65,751 4,341 61,410 4,392 1,190 3,202
Median age 52 [34, 71] 57 [36, 74] 52 [34, 71] 78 [71, 84] 79 [73, 86] 78 [71, 84] 75 [70, 82] 77 [71, 84] 75 [69, 81]
Age group
18-64 years 158,028 (66) 8,688 (59) 149,340 (66) -- -- -- -- -- --
≥65 years 82,948 (34) 5,933 (41) 77,015 (34) 65,751 (100) 4,341 (100) 61,410 (100) 4,392 (100) 1,190 (100) 3,202 (100)
Immunocompromised* -- -- -- 15,350 (23) 883 (20) 14,467 (24) 1,137 (26) 258 (22) 879 (28)
Updated from Link -Gelles, et al. MMWR: https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm
ED/UC = emergency department/urgent care; VISION data go through May 2025; IVY data go through April 2025
* Immunocompromised status is not evaluated for ED/UC encounters due to a higher likelihood of incomplete discharge diagnosis  codes in this setting.
21Effectiveness of 2024–2025 COVID -19 vaccination against COVID -19–associated emergency
department/urgent care  encounters by age group — VISION
September 2024 – May 2025
Updated from: Link -Gelles, et al. MMWR: https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm . Vaccine effectiveness was calculated by comparing the odds of 2024 –2025 COVID -19 vaccination in case -patients and control -patients using the equation: (1 – adjusted odds
ratio) x 100%. Odds ratios were estimated by multivariable logistic regression. The odds ratio was adjusted for age, sex, rac e and ethnicity, calendar day, and geographic region. The “no 2024 –2025 dose” group included all eligible persons who did not recei ve a 2024 –2025 COVID -19
vaccine dose, regardless of number of previous COVID -19 vaccine doses (if any) received.  * Time since vaccination is for most r ecent dose, which could have been an original monovalent, bivalent, 2023 -2024, or 2024 -2025 COVID -19 vaccine.Age group/2024 -2025 COVID -19 vaccination
status/days since doseCOVID -19
case -patients
N (Col %)COVID -19
control -patients
N (Col %)Median interval since
last dose among
vaccinated*, days (IQR) Adjusted vaccine effectiveness % (95% CI)
≥18 years
No 2024 -2025 COVID -19 dose  (Ref) 12,927 (88) 188,006 (83) 1,068 (742 -1,224) Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 1,694 (12) 38,349 (17) 89 (50 -129) 34 (30 -37)
2024 -2025 COVID -19 dose , 7–59 days earlier 572 (4) 11,763 (5) 34 (21 -47) 36 (30 -42)
2024 -2025 COVID -19 dose , 60–119 days earlier 695 (5) 14,685 (6) 89 (74 -104) 35 (29 -40)
2024 -2025 COVID -19 dose , 120 –179 days earlier 427 (3) 11,901 (5) 147 (133 -162) 28 (20 -35)
18-64 years
No 2024 -2025 COVID -19 dose  (Ref) 8,212 (95) 136,067 (91) 1,105 (866 -1,245) Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 476 (5) 13,273 (9) 86 (48 -127) 32 (25 -38)
2024 -2025 COVID -19 dose , 7–59 days earlier 156 (2) 4,244 (3) 33 (20 -46) 39 (29 -49)
2024 -2025 COVID -19 dose , 60–119 days earlier 199 (2) 5,155 (3) 89 (74 -104) 32 (21 -41)
2024 -2025 COVID -19 dose , 120 –179 days earlier 121 (1) 3,874 (3) 147 (132 -163) 20 (4 -34)
≥65 years
No 2024 -2025 COVID -19 dose  (Ref) 4,715 (79) 51,939 (67) 907 (448 -1,166) Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 1,218 (21) 25,076 (33) 91 (51 -131) 35 (30 -39)
2024 -2025 COVID -19 dose , 7–59 days earlier 416 (7) 7,519 (10) 34 (21 -47) 36 (29 -43)
2024 -2025 COVID -19 dose , 60–119 days earlier 496 (8) 9,530 (12) 90 (75 -105) 36 (29 -42)
2024 -2025 COVID -19 dose , 120 –179 days earlier 306 (5) 8,027 (10) 147 (133 -162) 30 (21 -39)
0 20 40 60 80 100
Vaccine effectiveness (%)
22Effectiveness of 2024–2025 COVID -19 vaccination against COVID -19–associated hospitalization
among immunocompetent  adults aged ≥65 years — VISION and IVY Networks
September 2024 – May 2025
Network/2024 -2025 COVID -19 vaccination status/days
since doseCOVID -19
case -
patients
N (Col %)COVID -19
control -
patients
N (Col %)Median interval since
last dose among
vaccinated*, days (IQR) Adjusted vaccine effectiveness % (95% CI)
VISION
No 2024 -2025 COVID -19 dose  (Ref) 2,943 (85) 34,900 (74) 958 (508 -1,187) Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 515 (15) 12,043 (26) 92 (51 -132) 44 (38 -50)
2024 -2025 COVID -19 dose , 7–59 days earlier 155 (4) 3,604 (8) 34 (20 -47) 46 (36 -54)
2024 -2025 COVID -19 dose , 60–119 days earlier 207 (6) 4,509 (10) 90 (75 -104) 50 (42 -57)
2024 -2025 COVID -19 dose , 120 –179 days earlier 153 (4) 3,930 (8) 147 (133 -162) 32 (19 -43)
IVY
No 2024 -2025 COVID -19 dose  (Ref) 822 (88) 1,824 (79) Not available Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 110 (12) 499 (21) 92 (55 –130) 46 (32 -58)
2024 -2025 COVID -19 dose , 7–59 days earlier 43 (5) 124 (5) 32 (20 –46) 42 (16 -60)
2024 -2025 COVID -19 dose , 60–119 days earlier 37 (4) 205 (9) 89 (73 –103) 53 (32 -68)
2024 -2025 COVID -19 dose , 120 –179 days earlier 30 (3) 170 (7) 146 (130 –161) 40 (9 -62)
0 20 40 60 80 100
Vaccine effectiveness (%)Updated from: Link -Gelles, et al. MMWR: https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm
Vaccine effectiveness was calculated by comparing the odds of 2024 –2025 COVID -19 vaccination in case -patients and control -patien ts using the equation: (1 – adjusted odds ratio) x 100%. Odds ratios
were estimated by multivariable logistic regression. For VISION, the odds ratio was adjusted for age, sex, race and ethnicity , calendar day, and geographic region. For IVY, the odds ratio was adjusted
for age, sex, race and ethnicity, geographic region (U.S. Department of Health and Human Services Region) and calendar time ( biweekly intervals). The “no 2024 –2025 dose” group included all eligible
persons who did not receive a 2024 –2025 COVID -19 vaccine dose, regardless of number of previous COVID -19 vaccine doses. VISION data go through May 2025; IVY data go through April 2025.
*Time since vaccination is for most recent dose, which could have been an original monovalent, bivalent, 2023 -2024, or 2024 -2025  COVID -19 vaccine.
23Effectiveness of 2024–2025 COVID -19 vaccination against COVID -19–associated critical illness
among immunocompetent  adults aged ≥65 years — VISION and IVY Networks
September 2024 – May 2025
2024 -2025 COVID -19 vaccination status/days since
doseCOVID -19
case -
patients
N (Col %)COVID -19
control -
patients
N (Col %)Median interval since
last dose among
vaccinated*, days (IQR) Adjusted vaccine effectiveness % (95% CI)
VISION
No 2024 -2025 COVID -19 dose  (Ref) 558 (85) 34,900 (74) 961 (510 -1,189) Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 97 (15) 12,043 (26) 92 (51 -132) 45 (31 -56)
2024 -2025 COVID -19 dose , 7–59 days earlier 28 (4) 3,604 (8) 34 (20 -47) 46 (21 -64)
2024 -2025 COVID -19 dose , 60–119 days earlier 44 (7) 4,509 (10) 90 (75 -104) 45 (25 -60)
2024 -2025 COVID -19 dose , 120 –179 days earlier 25 (4) 3,930 (8) 147 (133 -162) 43 (13 -62)
IVY
Acute respiratory failure
No 2024 -2025 COVID -19 dose  (Ref) 158 (88) 1,817 (78) Not available Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 21 (12) 498 (22) 96 (59 -131) 44 (11 -67)
ICU admission or death
No 2024 -2025 COVID -19 dose  (Ref) 141 (91) 1,824 (79) Not available Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 14 (9) 499 (21) 96 (60 -133) 56 (23 -76)
Invasive mechanical ventilation or death
No 2024 -2025 COVID -19 dose  (Ref) 74 (94) 1,824 (79) Not available Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 5 (6) 499 (21) 97 (60 -133) 70 (35 -89)
0 20 40 60 80 100
Vaccine effectiveness (%)
Based on methods in: Link -Gelles, et al. MMWR: https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm
Vaccine effectiveness was calculated by comparing the odds of 2024 –2025 COVID -19 vaccination in case -patients and control -patien ts using the equation: (1 – adjusted odds ratio) x 100%. Odds ratios were estimated by multivariable logistic regression. For VI SION,
the odds ratio was adjusted for age, sex, race and ethnicity, calendar day, and geographic region. For IVY, the odds ratio wa s adjusted for age, sex, race and ethnicity, geographic region (U.S. Department of Health and Human Services Region) and calenda r time
(biweekly intervals). The “no 2024 –2025 dose” group included all eligible persons who did not receive a 2024 –2025 COVID -19 vacci ne dose, regardless of number of previous COVID -19 vaccine doses. VISION data go through May 2025; IVY data go through April 202 5.
For VISION, critical illness is defined as admission to the intensive care unit or in -hospital death. For IVY, acute respiratory  failure was defined as new receipt of high -flow nasal canula, noninvasive ventilation, or invasive mechanical ventilation.
*Time since vaccination is for most recent dose, which could have been an original monovalent, bivalent, 2023 -2024, or 2024 -2025  COVID -19 vaccine.
ICU = intensive care unit
24Effectiveness of 2024–2025 COVID -19 vaccination against COVID -19–associated hospitalization
among immunocompromised  adults aged ≥65 years — VISION and IVY Networks
September 2024 – May 2025
Network/2024 -2025 COVID -19 vaccination status/days
since doseCOVID -19
case -
patients
N (Col %)COVID -19
control -
patients
N (Col %)Median interval since
last dose among
vaccinated*, days (IQR) Adjusted vaccine effectiveness % (95% CI)
VISION
No 2024 -2025 COVID -19 dose  (Ref) 719 (81) 10,035 (69) 882 (451 -1,166) Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 164 (19) 4,432 (31) 93 (53 -133) 38 (25 -48)
2024 -2025 COVID -19 dose , 7–59 days earlier 62 (7) 1,247 (9) 35 (20 -47) 25 (2 -43)
2024 -2025 COVID -19 dose , 60–119 days earlier 61 (7) 1,689 (12) 89 (75 -104) 47 (30 -60)
2024 -2025 COVID -19 dose , 120 –179 days earlier 41 (5) 1,496 (10) 147 (133 -163) 39 (14 -57)
IVY
No 2024 -2025 COVID -19 dose  (Ref) 214 (83) 670 (76) Not available Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 44 (17) 209 (24) 82 (48 -133) 36 (6 -57)
0 20 40 60 80 100
Vaccine effectiveness (%)
Updated from: Link -Gelles, et al. MMWR: https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm
Vaccine effectiveness was calculated by comparing the odds of 2024 –2025 COVID -19 vaccination in case -patients and control -patien ts using the equation: (1 – adjusted odds ratio) x 100%. Odds
ratios were estimated by multivariable logistic regression. For VISION, the odds ratio was adjusted for age, sex, race and et hnicity, calendar day, and geographic region. For IVY, the odds ratio was
adjusted for age, sex, race and ethnicity, geographic region (U.S. Department of Health and Human Services Region) and calend ar time (biweekly intervals). The “no 2024 –2025 dose” group included
all eligible persons who did not receive a 2024 –2025 COVID -19 vaccine dose, regardless of number of previous COVID -19 vaccine do ses (if any) received. VISION data go through May 2025; IVY data
go through April 2025.
* Time since vaccination is for most recent dose, which could have been an original monovalent, bivalent, 2023 -2024, or 2024 -2025 COVID -19 vaccine.
25IVY: Effectiveness of 2024–2025 COVID -19 vaccine against hospitalization
among adults aged ≥18 years by SARS -CoV-2 lineage using viral whole -
genome sequencing
•Population
•Cases:  COVID -like illness (CLI) and test positive for SARS -CoV-2*;restricted to patients with sequence -
confirmed†KP.3.1.1 lineage (Nextstrain  clade 24E)  or XEC lineage (Nextstrain  clade 24F)
•Controls: CLI and test negative forSARS -CoV-2, influenza viruses, and RSV (≥60 years) byRT-PCR
•Analytic Period: September 1, 2024 –April 27, 2025
•VE§ against hospitalization was calculated separately using case -patients with sequence -confirmed SARS -
CoV-2 KP .3.1.1 and XEC lineage infections
* Case patients who were co -infected with influenza viruses or RSV were excluded.
† Identification of a SARS -CoV-2 lineage through viral whole -genome sequencing was successful for 49% of case -patients during the  analysis period.
§ Vaccine effectiveness was calculated by comparing the odds of 2024 –2025 COVID -19 vaccination in case -patients and control -patien ts using the equation: (1 – adjusted odds ratio) x 100%.
Odds ratios were estimated by multivariable logistic regression.  The odds ratio was adjusted for age, sex, race and ethnicity, geographic region (U.S. Department of Health and Human Services
Region) and calendar time (biweekly intervals).
Lineage and 2024 -2025 COVID -19
vaccination statusCOVID -19 case -patients COVID -19 control -patients
Vaccine Effectiveness§% (95% CI)  N (Col %)Median interval
since last dose
among
vaccinated,
days (IQR) N (Col %)Median interval
since last dose
among
vaccinated,
days (IQR)
KP.3.1.1
No 2024 -2025 COVID -19 dose (Ref) 309 (91) Not available  5,202 (84) Not available  Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 29 (9) 56 (33 –75) 1,027 (16) 94 (57 –133) 45 (19 –64)
XEC
No 2024 -2025 COVID -19 dose (Ref) 173 (84) Not available  5,202 (84) Not available  Ref
Received 2024 -2025 COVID -19 dose 7–179 days earlier 32 (16) 87 (52 –112) 1,027 (16) 94 (57 –133) 34 (2 –57)
* These results include both immunocompetent and immunocompromised persons.
† KP.3.1.1 lineage was defined by Nextstrain  clade 24E and XEC lineage was defined by Nextstrain  clade 24F.
§ Vaccine effectiveness was calculated by comparing the odds of 2024 –2025 COVID -19 vaccination in case -patients and control -patien ts using the equation: (1 – adjusted odds ratio) x 100%. Odds ratios were
estimated by multivariable logistic regression.  The odds ratio was adjusted for age, sex, race and ethnicity, geographic region (U.S. Department of Health and Human Services Re gion) and calendar time
(biweekly intervals).-20 0 20 40 60 80 100
Vaccine  Effectiveness (%)IVY: Effectiveness of 2024–2025 COVID -19 vaccine against hospitalization
among adults aged ≥18 years* by SARS -CoV-2 lineage †
September 1, 2024 – April 27, 2025
27•For the respective year, compared to no in -season dose, COVID -19 vaccination provided additional protection
against:
-COVID -19-associated emergency department and urgent care* visits among children ; protection was generally similar across age
groups.
-COVID -19-associated emergency department and urgent care visits among adults .
-COVID -19-associated hospitalizations among adults aged ≥65 years with and without immunocompromising conditions .
-COVID -19-associated critical illness among adults aged ≥65 years ; protection appeared to be higher and more durable against critical
illness compared to less severe outcomes.
•VE should be interpreted as the added benefit of 2023 –2024 or 2024 –2025 COVID -19 vaccination in a population
with high levels of infection -induced immunity, vaccine -induced immunity, or both.
-Prior SARS -CoV-2 infection contributes protection against future disease, though protection wanes over time.
-An increase in SARS -CoV-2 circulation in the United States during late summer 2024, just before the 2024 –2025 COVID -19 vaccines
were approved and authorized, may have resulted in higher population -level immunity against JN.1 -lineage strains, which could ha ve
resulted in lower measured VE than in a population with less recent infection.Conclusions: effectiveness of COVID -19 vaccines
* Due to lower baseline rates of severe disease and lower COVID -19 vaccine coverage, VE against hospitalization and critical ill ness in children could not be estimated.
28Data and analysis were provided by CDC and the
following CDC -funded network partners:
VISION Collaborators
IVY Collaborators
Overcoming Collaborators
Back -up
30Context for interpreting COVID -19 VE across age groups: high infection -
induced seroprevalence in children and adults
* Data on persons aged 0 -17 years from nationwide commercial laboratory testing of residual serum specimens from ~27,000 childre n and adolescents originally submitted for routine screening or clinical management,
https://covid.cdc.gov/covid -data -tracker/#pediatric -seroprevalence
** Data on persons aged ≥16 years from a longitudinal, national cohort of ~35,000 blood donors, https://covid.cdc.gov/covid -data -tracker/#nationwide -blood -donor -seroprevalence -2022 89%
92%
87%
76%16-29 years
30-49 years
50-64 years
≥65 years
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent with infection -induced immunityPercent of persons with infection -induced immunity, based on anti -nucleocapsid results from blood donors,
adolescents and adults , October – December 2023**
VE findings should be interpreted as the added benefit provided by COVID -19 vaccination in a
population with a high prevalence infection -induced immunity.91%
93%0-11 years
12-17 yearsPercent of persons with infection -induced immunity, based on anti -nucleocapsid results from residual specimens from commercial l aboratories,
children and adolescents , November – December 2022*Age at blood draw
31Age group/2023 -2024 COVID -19 vaccination
status/days since doseTotal
encountersSARS -CoV -2-
test -positive,
N (%)Median interval since
last dose among
vaccinated, days (IQR) Adjusted VE (95% CI)
≥18 years
No 2023 -2024 COVID -19 dose (ref) 279,733 31,167 (11) 756 (543 -920) ref
2023 -2024 COVID -19 dose , 7-299 days earlier 65,906 5,929 (9) 117 (61 -189) 24 (21 to 26)
2023 -2024 COVID -19 dose , 7-59 days earlier 16,082 1,228 (8) 34 (21 -47) 49 (45 to 52)
2023 -2024 COVID -19 dose , 60-119 days earlier 17,653 1,521 (9) 88 (73 -103) 26 (22 to 30)
2023 -2024 COVID -19 dose , 120 -179 days earlier 13,815 875 (6) 147 (133 -163) 18 (12 to 24)
2023 -2024 COVID -19 dose , 180-299 days earlier 18,356 2,305 (13) 231 (204 -261) -7 (-13 to -2)
18-64 years
No 2023 -2024 COVID -19 dose (ref) 200,443 21,053 (10) 789 (624 -934) ref
2023 -2024 COVID -19 dose , 7-299 days earlier 23,655 1,893 (8) 116 (59 -187) 22 (18 to 26)
2023 -2024 COVID -19 dose , 7-59 days earlier 5,952 360 (6) 34 (20 -47) 55 (49 to 59)
2023 -2024 COVID -19 dose , 60-119 days earlier 6,285 436 (7) 88 (74 -104) 29 (22 to 36)
2023 -2024 COVID -19 dose , 120 -179 days earlier 4,971 256 (5) 147 (133 -163) 22 (11 to 31)
2023 -2024 COVID -19 dose , 180-299 days earlier 6,447 841 (13) 230 (203 -260) -24 ( -34 to -14)
≥65 years
No 2023 -2024 COVID -19 dose (ref) 79,290 10,114 (13) 669 (436 -868) ref
2023 -2024 COVID -19 dose , 7-299 days earlier 42,251 4,036 (10) 117 (62 -190) 25 (22 to 28)
2023 -2024 COVID -19 dose , 7-59 days earlier 10,130 868 (9) 34 (21 -47) 46 (41 to 50)
2023 -2024 COVID -19 dose , 60-119 days earlier 11,368 1,085 (10) 88 (73 -103) 25 (20 to 30)
2023 -2024 COVID -19 dose , 120 -179 days earlier 8,844 619 (7) 148 (133 -163) 19 (11 to 26)
2023 -2024 COVID -19 dose , 180-299 days earlier 11,909 1,464 (12) 232 (204 -262) 2 (-5 to 8)VISION: VE of 2023 -2024 COVID -19 vaccine against COVID -19-associated emergency
department/urgent care encounters among immunocompetent adults aged ≥18 years, by age group
September 2023 – August 2024
Link-Gelles et al. in press, JAMA Network Open. VE was calculated as (1 − odds ratio) x 100%, estimated using a test -negative case -control design, with the odds ratio adjusted for age, sex, race and ethnicity,
geographic region, and calendar time. A VE estimate less than zero is possible due to the waning protection from COVID -19 vaccin es coupled with the existing infection -induced immunity in unvaccinated
participants. As protection from vaccination wanes, and unvaccinated people accumulate protection from repeated infections, t his may yield negative VE. -40 -20 0 20 40 60 80 100
32VISION: VE of 2023 -2024 COVID -19 vaccine against COVID -19-associated
hospitalization among immunocompetent adults aged ≥18 years, by age group
September 2023 – August 2024
Age group/2023 -2024 COVID -19 vaccination
status/days since doseTotal
encountersSARS -CoV -2-
test -positive,
N (%)Median interval since
last dose among
vaccinated, days (IQR) Adjusted VE (95% CI)
≥18 years
No 2023 -2024 COVID -19 dose (ref) 87,718 8,480 (10) 733 (507 -918) ref
2023 -2024 COVID -19 dose , 7-299 days earlier 24,213 1,900 (8) 123 (63 -193) 29 (25 to 33)
2023 -2024 COVID -19 dose , 7-59 days earlier 5,618 417 (7) 34 (21 -47) 51 (46 to 56)
2023 -2024 COVID -19 dose , 60-119 days earlier 6,231 486 (8) 88 (74 -104) 36 (30 to 42)
2023 -2024 COVID -19 dose , 120 -179 days earlier 5,275 306 (6) 149 (134 -164) 22 (12 to 31)
2023 -2024 COVID -19 dose , 180-299 days earlier 7,089 691 (10) 230 (203 -260) -4 (-14 to 5)
18-64 years
No 2023 -2024 COVID -19 dose (ref) 35,303 2,229 (6) 788 (606 -940) ref
2023 -2024 COVID -19 dose , 7-299 days earlier 4,249 234 (6) 120 (62 -188) 15 (2 to 27)
2023 -2024 COVID -19 dose , 7-59 days earlier 1,005 60 (6) 33 (21 -46) 31 (10 to 47)
2023 -2024 COVID -19 dose , 60-119 days earlier 1,113 52 (5) 89 (75 -104) 33 (11 to 50)
2023 -2024 COVID -19 dose , 120 -179 days earlier 936 33 (4) 148 (135 -164) 21 ( -12 to 45)
2023 -2024 COVID -19 dose , 180-299 days earlier 1,195 89 (7) 229 (201 -259) -31 ( -66 to -4)
≥65 years
No 2023 -2024 COVID -19 dose (ref) 52,415 6,251 (12) 698 (467 -899) ref
2023 -2024 COVID -19 dose , 7-299 days earlier 19,964 1,666 (8) 123 (63 -194) 31 (27 to 35)
2023 -2024 COVID -19 dose , 7-59 days earlier 4,613 357 (8) 34 (21 -47) 54 (49 to 59)
2023 -2024 COVID -19 dose , 60-119 days earlier 5,118 434 (8) 88 (73 -104) 36 (29 to 42)
2023 -2024 COVID -19 dose , 120 -179 days earlier 4,339 273 (6) 149 (134 -164) 21 (10 to 31)
2023 -2024 COVID -19 dose , 180-299 days earlier 5,894 602 (10) 230 (204 -261) 0 (-10 to 10)
-80 -60 -40 -20 020 40 60 80 100Link-Gelles et al. in press, JAMA Network Open. VE was calculated as (1 − odds ratio) x 100%, estimated using a test -negative case -control design, with the odds ratio adjusted for age, sex, race and ethnicity,
geographic region, and calendar time. A VE estimate less than zero is possible due to the waning protection from COVID -19 vaccin es coupled with the existing infection -induced immunity in unvaccinated
participants. As protection from vaccination wanes, and unvaccinated people accumulate protection from repeated infections, t his may yield negative VE.
IVY: Number of COVID -19 case -patients by hospital admission week and SARS -
CoV-2 lineage
September 1, 2024 –April 27, 2025
Dates are for the start of the admission week.

34*Data sources included Medicare Enrollment Database (EDB) and Common Medicare Environment (CME), Common Working File (CWF) an d Shared System Data (SSD) Medicare Parts A/B claims data, Minimum Data Set (MDS), and CDC/ATSDR
Social Vulnerability Index (SVI)
**Hazard ratios adjusted for age group, sex, race, long/short nursing home stay status, social vulnerability index, state, ru ral/urban classification, number of underlying medical conditions, 2022 -2023 influenza vaccination status, and bivalent
COVID -19 vaccination status.Medicare data
• Design: Retrospective cohort
• Data source:  Medicare fee -for-service claims data*
• Population:  Persons aged ≥65, recent nursing home
stay
• Censoring events:
– COVID -19-associated thromboembolic event (TE)
– Death
– Disenrollment in Medicare Parts A/B
– Enrollment in Medicare Part C
– Admission to hospice facility
– Dialysis encounter
– Receipt of a 2023 -2024 COVID -19 vaccine dose <60 days from
bivalent COVID -19 vaccine dose
– Receipt of a second 2023 -2024 COVID -19 vaccine dose <120 days
from first 2023 -2024 COVID -19 vaccine dose
– Receipt of a third 2023 -2024 COVID -19 vaccine dose
– End of study period
• VE = (1 - adjusted hazard ratio**) x 100%
where adjusted hazard ratio = 𝑟𝑎𝑡𝑒  𝑜𝑓 𝐶𝑂𝑉𝐼𝐷 −19−𝑎𝑠𝑠𝑜𝑐𝑖𝑎𝑡𝑒𝑑  𝑇𝐸𝑣𝑎𝑐𝑐𝑖𝑛𝑎𝑡𝑒𝑑
𝑟𝑎𝑡𝑒  𝑜𝑓 𝐶𝑂𝑉𝐼𝐷 −19−𝑎𝑠𝑠𝑜𝑐𝑖𝑎𝑡𝑒𝑑  𝑇𝐸𝑢𝑛𝑣𝑎𝑐𝑐𝑖𝑛𝑎𝑡𝑒𝑑
COVID -19 TEOther Censoring Event
Unvaccinated person -time
Vaccinated person -time
Start Follow -up End Study Period
35Age group/2023 -2024 COVID -19 vaccination
status/days since doseNumber of
BeneficiariesNumber of
OutcomesMedian Follow -up Time
Contributed to Category
(Days) Adjusted VE (95% CI)
≥65+ years
No 2023 -2024 COVID -19 dose (ref) 516,176 4,335 142 Ref
2023 -2024 COVID -19 dose , ≥ 7 days earlier 209,228 726 161 31% (25%, 36%)
2023 -2024 COVID -19 dose , 7-59 days earlier 26,646 198 53 50% (42%, 56%)
2023 -2024 COVID -19 dose , 60-119 days earlier 37,426 238 60 29% (20%, 38%)
2023 -2024 COVID -19 dose , 120 -179 days earlier 23,558 138 60 15% (0%, 28%)
2023 -2024 COVID -19 dose , ≥ 180  days earlier 121,598 152 65 0% ( -17%, 14%)
65-74 years
No 2023 -2024 COVID -19 dose (ref) 116,278 1,025 176 Ref
2023 -2024 COVID -19 dose , ≥ 7 days earlier 40,719 132 178 29% (16%, 39%)
2023 -2024 COVID -19 dose , 7-59 days earlier 5,029 34 53 47% (36%, 57%)
2023 -2024 COVID -19 dose , 60-119 days earlier 6,646 55 60 26% (11%, 39%)
2023 -2024 COVID -19 dose , 120 -179 days earlier 4,984 22 60 12% ( -9%, 29%)
2023 -2024 COVID -19 dose , ≥ 180  days earlier 24,060 21 64 -5% ( -29%, 15%)
≥75+ years
No 2023 -2024 COVID -19 dose (ref) 399,898 3,310 135 Ref
2023 -2024 COVID -19 dose , ≥ 7 days earlier 168,509 594 157 31% (25%, 37%)
2023 -2024 COVID -19 dose , 7-59 days earlier 21,617 164 53 50% (42%, 57%)
2023 -2024 COVID -19 dose , 60-119 days earlier 30,780 183 60 30% (20%, 39%)
2023 -2024 COVID -19 dose , 120 -179 days earlier 18,574 116 60 16% (1%, 29%)
2023 -2024 COVID -19 dose , ≥ 180  days earlier 97,538 131 65 1% ( -17%, 16%)VE of 2023 -2024 COVID -19 vaccine against COVID -19 related thromboembolic events among immunocompetent
Medicare fee -for-service beneficiaries residing in a nursing home, by age group and time since vaccination
September 2023 – July 2024
-40 -20 0 20 40 60 80 100
CDC, unpublished data
Models are adjusted for age group, sex, race, long/short NH stay status, social vulnerability index (SVI), state, rural/urban classification, number of UMC categories, 2022 -2023 influenza vaccination status, and bivalent COVID -19 vaccination
status.
Infection -induced SARS -CoV-2 seroprevalence among U.S.
children — September 2021 – December 2022
36
Infection -induced (nucleocapsid
antibody) seroprevalence
Month and Year
Shaded ranges depict 95% confidence intervals for the estimated seroprevalence shown by the dark line in the corresponding co lor.
Source: https://covid.cdc.gov/covid -data -tracker/#pediatric -seroprevalence
Accessed: March 20, 20256-11 months
Population SARS -CoV -2 spike antibody over time by the cumulative
number of combined infections and vaccinations - U.S. blood donors ages
≥16 years, September 2021 -December 2023
Solid lines represent mean anti -spike IgG levels; dotted lines represent model based 25th-75th% percentiles
Higher number of cumulative SARS -CoV-2 infections and COVID -19 vaccinations leads to higher antibody
levels, but with smaller incremental increases in antibodies with each exposure
Spike IgG BAU/mL
Source: https://covid.cdc.gov/covid -data -tracker/#nationwide -blood -donor -seroprevalence -2022 , CDC unpublished data 9
381. Yousaf AR, Mak J, Gwynn L, et al. COVID -19 Vaccination and Odds of Post –COVID -19 Condition Symptoms in Children Aged 5 to 17 Years. JAMA Netw Open. 2025;8(2):e2459672.
2. Mak J, Khan S, Britton A et al. Association of Messenger RNA Coronavirus Disease 2019 (COVID -19) Vaccination and Reductions i n Post COVID Conditions Following Severe Acute Respiratory Syndrome
Coronavirus 2 Infection in a US Prospective Cohort of Essential Workers, The Journal of Infectious Diseases, Volume 231, Issu e 3, 15 March 2025, Pages 665 –676COVID -19 mRNA vaccination associated with reduced occurrence
of Long COVID following COVID -19: June 2021 -September 2022
Among children aged 5 – 17 years:
Completion of the primary vaccine
series prior to infection associated
with reduced likelihood of Long
COVID symptoms1
•57% for 1 or more symptoms
•73% for 2 or more symptoms
•72% for respiratory symptomsAmong adults:
3 doses of original monovalent vaccine
prior to infection associated with
reduced likelihood of Long COVID
symptoms2
•63% for gastrointestinal symptoms
•44% for neurological symptoms
•52% for other non -specific
symptoms
•Data that explicitly quantifies vaccine effectiveness against transmission is ideal,
but it is often not feasible.
•Other data can help us understand the impact of COVID -19 vaccination on
transmission, vaccine effectiveness against infection and infectiousness
-COVID -19 vaccines provide moderate protection against infection in older children and adults.1,2,3
-COVID -19 vaccines may provide less protection against infection in young, infection -naïve
children.4
-COVID -19 vaccines moderately reduce infectiousness in individuals after they are infected with
SARS -CoV-2 (see next slides).5
•Preventing infections further reduces transmission by stopping future transmission
chains. COVID -19 vaccine impact on transmission
1 Feldstein L, et al. Effectiveness of mRNA COVID -19 Vaccines and Hybrid Immunity in Preventing SARS -CoV-2 Infection and Symptomatic COVID -19 Among Ad ults in the United States.
https://academic.oup.com/jid/article/231/4/e743/7945315
2 Feldstein L , et al. Effectiveness of Bivalent mRNA COVID -19 Vaccines in Preventing SARS -CoV-2 Infection in Children and Adolescents Aged 5 to 17 Yea rs. https://jamanetwork.com/journals/jama/fullarticle/2814536
3 Kirwan PD, et al. Protection of vaccine boosters and prior infection against mild/asymptomatic and moderate COVID -19 infection in the UK SIREN hea lthcare worker cohort: October 2023 to March 2024.
https://www.sciencedirect.com/science/article/pii/S0163445324002275?via%3Dihub
4 Feldstein L , et al. Protection From COVID -19 Vaccination and Prior SARS -CoV-2 Infection Among Children Aged 6 Months –4 Years, United States, Septemb er 2022 –April 2023
https://academic.oup.com/jpids/article/14/1/piae121/7917119
5 CDC. Respiratory Illness: Gauge of Household Transmission (RIGHT) Study, unpublished with manuscript in progress.
40COVID -19 Vaccine Effectiveness against SARS -CoV-2 (SCV2) Infectiousness
Respiratory  Illness: Gauge of Household Transmission (RIGHT) Study
Prospective household transmission study of SARS -CoV-2, January 2024 –January 2025
Preliminary analysis (unpublished, manuscript in progress) from RIGHT Study shared by research teams at CDC, Vanderbilt Unive rsity Medical Center, University of Washington, and Columbia
University Irvin Medical Center.
Individuals with SARS -CoV-2 infection who had received a COVID -19
vaccination within prior 6 months had lower risk of transmitting to other
household contacts. Vaccine effectiveness at reducing transmission to
others was 45%.
Preliminary analysis (unpublished, manuscript is progress) from RIGHT Study Jan 2024 -Jan 2025 shared by research teams at CDC, V anderbilt University Medical Center, University of Washington, and
Columbia University Irvin Medical Center. *Adjusted for age of contact, COVID -19 vaccination status of contact, age of primary case, enrollment state, number of people in  the
home, enrollment timing, and clustering by household
† Vaccine effectiveness against infectionAdjusted* Risk of SARS -CoV-2 Infection in Household Contact by Primary Case Vaccination Status
†

Summary: Updates to COVID -19 Vaccine Effectiveness COVID -19 Session Coronavirus and Other Respiratory Viruses Division June 25, 2025National Center for Immunization and Respiratory Diseases   2•Vaccine effectiveness methods & context •Estimates of COVID -19 Vaccine Effectiveness in Children •Estimates of COVID -19 Vaccine Effectiveness in Adults •ConclusionsAgenda –COVID -19 vaccine effectiveness (VE) Methods & Context 3 4 Case ControlPerson with acute respiratory illness SARS -CoV-2 test COVID -19 …


04 Meyer COVID 508

Update on CDC’s COVID-19 Vaccine Safety Monitoring
Sarah Meyer, MD MPH
Director, CDC’s Immunization Safety Office
June 25, 2025
1

        Key Points
• CDC and interagency partners launched an extensive vaccine safety monitoring
program for COVID-19 vaccines
• Many potential safety outcomes were rigorously assessed through complementary passive and active systems
• Myocarditis is causally associated with mRNA COVID-19 vaccines
-Adverse events common to all vaccines were also observed (e.g., local and
systemic reactions, allergic reactions)
• CDC continues to monitor the safety of COVID-19 vaccines
2

Interagency collaboration to
monitor post-licensure safety
CDC
monitoring
starts
3

        CDC’s Immunization Safety Office Monitors Vaccine Safety
Through Strong, Complementary Systems
VAERS VSD CISA Project V-safe
1990 1990 2001 2020
Systems work together to rapidly detect and assess potential
safety concerns to help inform public health actions
4

VAERS
Vaccine Adverse Event Reporting System (VAERS)
The Nation’s Early Warning System for Vaccine Safety
• Co-managed by CDC and FDA
• Nationwide spontaneous reporting system that can rapidly
detect safety signals, including rare events
• Mandated reporting by healthcare providers and
manufacturers, and encouraged from anyone (e.g., patients)
• A report to VAERS does not mean that a vaccine caused an adverse event
• Used for signal detection and hypothesis generation, not
typically for assessing causality
5

      Vaccine Safety Datalink (VSD)
Collaborative Model for High-Quality Vaccine Safety Data
VSD • 13 integrated healthcare organizations, covering >15.5
million people per year
• Acti
ve monitoring using electronic medical records (EMR)
and chart reviews
• Rapid monitoring for pre-specified events as well as
monitoring for unexpected events
• Can detect and assess safety signals
• Develops innovative methods for monitoring safety
6

          Clinical Immunization Safety Assessment (CISA) Project
Network to Guide Vaccine Safety from the Individual to Population Level
CISA Project • 8 medical research centers with vaccine safety experts
• Pro
vides expert clinical consultation on complex
immunization issues
• Conducts clinical research on vaccine safety
• Helps to inform CDC public health guidance on clinical
immunization safety issues
7

V-safe: After-Vaccination Health Checker
CDC’s Tool for Direct-to-Consumer Vaccine Safety Monitoring
V-safe • Web-based, self-reported active monitoring system
established during COVID-19 pandemic
• Can ser
ve as earliest source of information for new
vaccines and in populations excluded from clinical trials
-Used to recruit women for COVID-19 Vaccine Pregnancy
Registry
• Important tool for emergency preparedness and response
• Integrated with VAERS to help streamline reporting of
ser
ious adverse events
8

   CDC’s Comprehensive Approach to Studying COVID-19 Vaccine Safety
Surveillance Epidemiologic studies Clinical Research Pregnancy Registry
Ana
lyze spontaneously Assess specific safety Safety studies to guide Longitudinal assessment of
reported events questions clinical practice maternal and infant outcomes
Rapid cycle analyses Dat a mining Pati ent surveys
Qui
ckly detect potential Ass
ess >60,000 outcomes Ass
ess symptoms and
con
cerns for investigation for
unexpected events hea
lth impacts
9

                   CDC Summary of COVID-19 Vaccine Safety Data Based on
Comprehensive Body of Evidence Collected
December 2020 – June 2025
17 28 29 114 ~9.6M
VaST work
group reports Advisory
meeting
presentations
(ACIP, VRBPAC) Morbidity and
Mortality Weekly
Report (MMWR)
publications Published
manuscripts Participants
enrolled in V-safe
Vaccine doses distributed in U.S. ~1B
ACIP: Advisory Committee on Immunization Practices; VRBPAC: Vaccines and Related Biological Products Advisory Committee; VaST: Vaccine Safety Technical Work Group 10

 mRNA
Pfizer-BioNTech
Moderna Three Types of COVID-19 Vaccine Received FDA
Authorization or Approval in the United States
Protein-based
Novavax
Viral Vector
Janssen
11

     -Janssen Use Limited After Detection of Safety Concerns in
April 2021, and No Longer Authorized in U.S. as of June 2023
Protein-based
Novavax
mRNA
Pfizer-BioNTech
Moderna
EUA: Emergency Use Authorization
Oliver S, et al. Development of COVID-19 vaccine policy — United States, 2020–2023 - ScienceDirect
Viral Vector
Janssen
• By April 2021, VAERS detects 6 reports of
thrombosis w/ thrombocytopenia
syndrome (TTS); FDA and CDC issue a 10
day pause in use before resuming
• In December 2021, ACIP issues preferential
recommendation for mRNA vaccines
• In June 2023, FDA revokes EUA
12

            Janssen Use Limited After Detection of Safety Concerns in
April 2021, and No Longer Authorized in U.S. as of June 2023
Protein-based
Novavax
mRNA
Pfizer-BioNTech
Moderna
EUA: Emergency Use Authorization
Oliver S, et al. Dev
elopment of COVID-19 vaccine policy — United States, 2020–2023 - ScienceDirect
Viral Vector
Janssen
Highlights an example of
federal safety systems
working to rapidly
identify and mitigate a
vaccine safety issue
13

    mRNA
Pfizer-BioNTech
Moderna -Limited Post-Authorization Safety Data Available for Novavax
Protein-based
Novavax
Limited post authorization safety data
available:
• Authorized later than other products (July 2022)
• Limited uptake in the U.S.
mRNA
Pfizer-BioNTech
Moderna
Viral Vector
Janssen
14

 mRNA
Pfizer-BioNTech
Moderna Focus on mRNA COVID-19 Vaccines For This Presentation
Protein-based
Novavax
Viral Vector
Janssen
15

   Monitoring Safety of COVID-19 Vaccines
What we have learned
16
16

         CDC Has Evaluated At Least 65 Specific Outcomes to Assess COVID-19
Vaccine Safety Using a Variety of Systems and Epidemiologic Methods
Acute myocardial infarction • ICU admission • Acute disseminated encephalomyelitis • Thrombotic
thrombocytopenic Purpura • Encephalopathy • Gestational diabetes • Trigeminal neuralgia and
related disorders • Meningitis • Deep vein thrombosis • Anaphylaxis • Thrombocytopenia •
Postmenopausal bleeding • Myocarditis • Cataplexy • Myelitis • Chronic inflammatory demyelinating
polyneuropathy • Non-COVID mortality • Pulmonary embolism • Stillbirth • Major birth defects •
Encephalitis •Local reactions •Vaccine-Associated Enhanced Disease after COVID-19 Vaccines
• Hemorrhagic stroke • Administration errors • Acute respiratory distress syndrome • Narcolepsy •
Perinatal death •Bell's Palsy •Thrombosis with thrombocytopenia syndrome •Multiple sclerosis
• Systemic reaction
s • Spontaneous abortion • Ataxia • Hospitalization • Acute disseminated
encephalomyelitis • Menstrual irregularities • Immune thrombocytopenic purpura • All-cause
mortality • Pericarditis •Early childhood infections in infants of vaccinated mothers •Ischemic stroke
• Shoulder injuries • Multisystem Inflammatory Syndrome in Children • Multisystem Inflammatory
Syndrome in Adults • Tinnitus • Disseminated intravascular coagulation • Acute respiratory distress
syndrome • Venous thromboembolism • Arthritis • Seizure • Kawasaki Disease • Arthralgia •
Menstrual irregularities •NICU admission •Chronic inflammatory demyelinating polyneuropathy
•Small-for-gestational age •Post-COVID conditions •Trigeminal neuralgia and related disorders
17

Weekly, Sequential Monitoring of
Pre-Specified Outcomes in the VSD
• Rapid cycle analyses (RCAs) conducted weekly since December 2020
of up to 23 pre-specified outcomes among over 12 million people
-Outcomes selected based on clinical trial data, known safety
findings with other vaccines, or biological plausibility
• Seq
uential statistical testing using automated ICD-10-CM codes
-Compare incidence in vaccinated people during post-vaccination
risk interval vs. vaccinated people in a comparison window
• If p
otential “statistical signal” detected, additional analyses and/or
chart reviews conducted
-System designed to be sensitive; not all detected signals
represent a true safety concern
18

     Evaluation of Statistical Signals Detected for mRNA COVID-19
Vaccines through VSD’s Rapid Cycle Analyses – 2020-2025
8 statistical signals detected
Acute myocardial infarction
 Seizure
Age 18+ years 18-64 years
Immune Thrombocytopenic Purpura
Age 65+ years
Venous thromboembolism
Age 12+ years Guillain-Barré syndrome
Age 65+ years
Bell’s Palsy
Age 12+ years
Ischemic stroke
Age 50+ years
Myocarditis
Age 12+ years
COVID-19 Vaccine Safety Technical (VaST) Work Group: Enhancing vaccine safety monitoring during the pandemic – ScienceDirect and CDC unpublished data 19

  Evaluation of Statistical Signals Detected for mRNA COVID-19
Vaccines through VSD’s Rapid Cycle Analyses – 2020-2025
Acute myocardial infarction
Age 65+ years
Venous thromboembolism
Age 12+ years
Bell’s Palsy
Age 12+ years
Ischemic stroke
Age 50+ years
Guillain-Barré syndrome
Age 65+ years
Seizure
18-64 years
Immune Thrombocytopenic Purpura
Age 65+ years
Myocarditis
Age 12+ years 8 statistical signals detected Further investigations
Chart reviews
Trend analysis
Additional studies
(e.g., self-controlled
case series)
Query other
systems
COVID-19 Vaccine Safety Technical (VaST) Work Group: Enhancing vaccine safety monitoring during the pandemic – ScienceDirect and CDC unpublished data 20

       Evaluation of Statistical Signals Detected for mRNA COVID-19
Vaccines through VSD’s Rapid Cycle Analyses – 2020-2025
Acute myocardial infarction
Age 65+ years
Venous thromboembolism
Age 12+ years
Bell’s Palsy
Age 12+ years
Ischemic stroke
Age 50+ years
Guillain-Barré syndrome
Age 65+ years
Seizure
18-64 years
Immune Thrombocytopenic Purpura
Age 65+ years
Myocarditis
Age 12+ years 8 statistical signals detected Further investigations
system
Chart reviews
Trend analysis
Additional studies
(e.g., self-controlled
case series)
Query other
COVID-19 Vaccine Safety Technical (VaST) Work Group: Enhancing vaccine safety monitoring during the pandemic – ScienceDirect and CDC unpublished data
Increased risk for myocarditis
following mRNA COVID-19 vaccines
No clear or consistent evidence of
a safety concern for the others
Safety assessment
21

    38
6
22Myocarditis Following mRNA COVID-19 Vaccination Among
People Ages 12–39 Years in the Vaccine Safety Datalink
Incidence of myocarditis within 7 days of vaccination per million mRNA vaccine doses administered
*
6 38
25
2 5
2
Dose 1
Original monovalent Dose 2
Original monovalent Booster
Original monovalent Bivalent
2020-2021 2021-2022 2022-2023 2023-2024 2024-2025 *
Background
<2 per million higher in males
• Myocarditis rare in children aged <12 years
and adults aged ≥50 years
* • Rates peak at age 16-17 years and are
rate
*St
atistically significant increased rate ratio in vaccinated concurrent comparator analysis. Source: CDC Immunization Safety Office 22

                     Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination in
FDA’s Biologics Effectiveness and Safety System (BEST), 2023—2024 Season
Incidence (cases per million doses) during days 1—7 following vaccine administration
FDA issued Safety Labeling Change (SLC) notification letters to the manufacturers
on April 17, 2025, and initiated the SLC process to include new safety information on myocarditis and pericarditis for
Comirnaty and Spikevax. Under the labeling negotiations, FDA has notified sponsors of the above data
2025 Safety and Availability Communications | FDA ; Information courtesy of FDA 23

        Follow-up CDC Studies Demonstrate Most Adolescents
and Young Adults Have Recovered From Myocarditis
• Surveys of individuals aged 12-29 years with myocarditis after mRNA COVID-19 vaccine, and their
healthcare providers, for whom a VAERS report was filed during January 12-November 5, 2021
• Based on cardiologist or other healthcare provider assessment:
83% >90%
Fully or probably fully recovered by at Overall, fully or probably fully recovered by
leas
t 90 days after myocarditis onset at least a 1 year after myocarditis onset
• Among patients with abnormal cardiac MRI at 1-year evaluation, most common abnormality was late ga
dolinium enhancement
-clinical significance unclear; majority considered recovered and cleared for all physical activity
• No k
nown deaths or cardiac transplants
Outcomes at least 90 days since onset of myocarditis after mRNA COVID-19 vaccination in adolescents and young adults in the USA: a follow-up surveillance study - The Lancet Child & Adolescent
Health ; Outcomes at ≥1 year based on unpublished data 24

                     COVID-19 Vaccine Safety in Children Ages 6 Months to 11 Years
• Risk of myocarditis following COVID-19 vaccines in children aged <12 years is low,
par
ticularly for those aged 6 months to 5 years
-Active, sequential analyses in the Vaccine Safety Datalink have demonstrated no statistical signals
for
myocarditis in children
-No confirmed myocarditis cases in children aged <5 years in VAERS or VSD
• Rapid cycle analyses in the VSD demonstrate no increased risks for 22 other pre -
specified outcomes following COVID-19 vaccination
• Evaluations to assess multisystem inflammatory syndrome in children (MIS-C) following COVID-19 vaccination demonstrated that most patients had evidence of preceding SARS-CoV-2 infection
Safety of COVID-19 Vaccination in United States Children Ages 5 to 11 Years | Pediatrics | American Academy of Pediatrics ; Safety Monitoring of mRNA COVID-19 Vaccine Third Doses Among Children Aged 6 Months–5 Years — United States, June 17, 2022–May 7, 2023 |
MMWR ; COVID-19 Vaccine Safety First Year Findings in Adolescents | Pediatrics | American Academy of Pediatrics ; Safety Monitoring of Bivalent COVID-19 mRNA Vaccine Booster Doses Among Children Aged 5–11 Years — United States, October 12–January 1, 2023 |
MMWR ; COVID-19 mRNA Vaccine Safety Among Children Aged 6 Months–5 Years — United States, June 18, 2022–August 21, 2022 | MMWR ; Safety of COVID-19 mRNA Vaccination Among Young Children in the Vaccine Safety Datalink | Pediatrics | American Academy of
Pediatrics ; Surveillance for Multisystem Inflammatory Syndrome in US Children Aged 5-11 Years Who Received Pfizer-BioNTech COVID-19 Vaccine, November 2021 through March 2022 – PubMed ; Reported cases of multisystem inflammatory syndrome in children aged
12–20 years in the USA who received a COVID-19 vaccine, December, 2020, through August, 2021: a surveillance investigation - The Lancet Child & Adolescent Health 25

          Majority of COVID-19 Vaccine Reports to VAERS in Children Aged
<12 Years Include at Least One Vaccine Administration Error
Approximately 77% of reports in children aged 6 months-4 years and 70% of reports in children aged 5-11 years
related to administration errors between October 21, 2021 – April 30, 2025
Data source: https://wonder.cdc.gov
VAERS reports may include more than one administration error type 26

    CDC Is Expanding Its Work to Prevent Vaccine
Administration Errors
Vaccine Administration Protocols | CDC 27
Evaluating Safety of COVID-19 Vaccines in Pregnant Women
• >23,000 pregnant women CDC COVID-19 Vaccine Pregnancy Registry
• 7 analyses
• Ob
servational studies based on survey
and medical record information
• >45,000 pregnant women Vaccine Safety Datalink
• 11 an
alyses to date
• Cohort
, case-control, and surveillance
evaluations

28

             COVID-19 Vaccine Safety During Pregnancy
Across CDC studies, evidence shows NO increased risk of:
Materna
l outcomes Pregnancy outcomes Infant outcomes
 25 medically-attended  Miscarriage  Major birth defects
adverse events  Stillbirth  Neonatal ICU admission
 Serious adverse events  Preterm birth  Infant death
 Pregnancy-related  Small-for-gestational age
condi
tions
 Maternal ICU admission
Evaluation of Acute Adverse Events after Covid-19 Vaccination during Pregnancy | New England Journal of Medicine ; Receipt of COVID-19 Vaccine During Pregnancy and Preterm or Small-for-Gestational-Age at Birth — Eight Integrated Health Care
Organizations, United States, December 15, 2020–July 22, 2021 | MMWR ; Receipt of mRNA Covid-19 Vaccines and Risk of Spontaneous Abortion | New England Journal of Medicine ; Spontaneous Abortion Following COVID-19 Vaccination During
Pregnancy | Public Health | JAMA | JAMA Network ; COVID-19 Booster Vaccination in Early Pregnancy and Surveillance for Spontaneous Abortion; Coronavirus Disease 2019 (COVID-19) Vaccination and Stillbirth in the Vaccine Safety Datalink ;
Medically Attended Acute Adverse Events in Pregnant Women ; Obstetric Complications and Birth Outcomes After Antenatal Coronavirus Disease 2019 (COVID-19) Vaccination; COVID-19 Vaccination in the First Trimester and Major Structural Birth
Defects Among Live Births ; Accumulating Robust Evidence for Reducing Vaccine Hesitancy in Early Pregnancy—Reply 29

      Address Vaccine Safety
Tinnitus
• Conducted data mining to assess tinnitus:
-VAERS empirical Bayesian data mining did not find
disproportionate reporting of tinnitus
-VSD tree-based data mining found no signals for tinnitus
• Taken together, findings do not support an
inc
reased risk of tinnitus after COVID-19 vaccine
Postmenopausal Bleeding After Coronavirus Disease 2019 (COVID-19) Vaccination: Vaccine Adverse Event Reporting System – PubMed
Menstrual irregularities and vaginal bleeding after COVID-19 vaccination reported to v-safe active surveillance, USA in December, 2020-January, 2022: an observational cohort study – PubMed Tinnitus after COVID-19 vaccination: Findings from the vaccine adverse event reporting system and the vaccine safety datalink - ScienceDirect Examples of CDC Studies to
Concerns from the Public
Abnormal uterine bleeding
• Conducted studies in VAERS, VSD, and v-safe for
ab
normal uterine bleeding
• VSD studies demonstrated:
-Availability of COVID-19 vaccines was not associated
with a change in incidence of medically-attended
abnormal uterine or post-menopausal bleeding
-Receipt of COVID-19 vaccine not associated with
greater bleeding severity
Abnormal uterine bleeding diagnoses and care following COVID-19 vaccination – ScienceDirect
Postmenopausal bleeding after COVID-19 vaccination – PubMed
30

            Safety Monitoring of Death Reports Following mRNA COVID -
19 Vaccination in VAERS
• As of May 30, 2025, there have been 19,417 domestic deaths reported to VAERS
after COVID-19 vaccination
• Important considerations related to evaluation of death reports in VAERS
-FDA Emergency Use Authorizations and CDC COVID-19 Vaccination Provider Enrollment
Agreements required healthcare provider to report all deaths following COVID-19 vaccination to
VAERS, regardless of cause or circumstances surrounding death (requirement does not apply to
oth
er vaccines)
-VAERS generally cannot assess causality of adverse reports, including deaths
• We conducted an evaluation of deaths following mRNA COVID-19 vaccination in VAERS
thr
ough January 31, 2023
Vaccine Adverse Event Reporting System. VAERS Reporting Information for COVID-19 Vaccines. https://vaers.hhs.gov/reportevent.html 31

 Safety Monitoring of Death Reports Following mRNA*COVID-19
Vaccination in VAERS – December 22, 2020 – January 31, 2023
Deaths reported in VAERS
CDC requests
medical records
Excluded
12,849 wi
th cause of death : • 1,790 re
ports of vaccine types 17,631 do
mestic VAERS 17,579 re
ports with verified death after • Autopsy: 673 othe
r than mRNA repo
rts of death following review by CDC clinician • Death certification: 8,862 • 2,940 wi
thout cause of death COVI
D-19 vaccine • Medical records: 2,576 (52 de
termined not to be a death) info
rmation available • VAER
S report alone: 738
* Includes reports with missing vaccine type, but excludes reports known to be after Janssen or Novavax COVID-19 vaccine
Reports to the Vaccine Adverse Event Reporting System (VAERS) reviewed and processed during December 22, 2020 — January 31, 2023; reported date of vaccination during December 22, 2020 — January 31, 2023 or missing 32

                              Safety Monitoring of Death Reports Following mRNA*COVID-19
Vaccination in VAERS – December 22, 2020 – January 31, 2023
17,631 domestic VAERS
reports of death following
COVID-19 vaccine
12,849 with cause of death :
• Autopsy: 673
• Death certification: 8,862
• Medical records: 2,576
• VAERS report alone: 738 17,579 reports with verified death after
review by CDC clinician
(52 determined not to be a death)
CDC requests
medical records
National Center for Health Statistics
Multiple Cause of Death Database
Death certificates
from U.S. residents
Cause of death categorized
by ICD-10 diagnostic codes Deaths reported in VAERS
• 1,790 reports of vaccine types
other than mRNA
• 2,940 without cause of death information available Ex
cluded
Deaths reported in general U.S. population
* Includes reports with missing vaccine type, but excludes reports known to be after Janssen or Novavax COVID-19 vaccine
Rep
orts to the Vaccine Adverse Event Reporting System (VAERS) reviewed and processed during December 22, 2020 — January 31, 2023; reported date of vaccination during December 22, 2020 — January 31, 2023 or missing 33

 Safety Monitoring of Death Reports Following mRNA*COVID-19
Vaccination in VAERS – December 22, 2020 – January 31, 2023
17,631 domestic VAERS
reports of death following
COVID-19 vaccine 12,849 with cause of death :
• Autopsy: 673
• Death certification: 8,862
• Medical records: 2,576
• VAERS report alone: 738 17,579 reports with verified death after
review by CDC clinician
(52 determined not to be a death)
National Center for Health Statistics
Multiple Cause of Death Database Death certificates
from U.S. residents Cause of death categorized
by ICD-10 diagnostic codes Deaths reported in VAERS
Observed Rate
Number of deaths (cause-specific)
100,000 persons vaccinated
Within 42 days of vaccination
Expected Rate
Number of deaths (cause-specific)
100,000 persons in U.S. population
Within 42 days of vaccination • 1,790 reports of vaccine types
other than mRNA
• 2,940 without cause of death information available Exclud
ed
Deaths reported in general U.S. population
* Includes reports with missing vaccine type, but excludes reports known to be after Janssen or Novavax COVID-19 vaccine
Reports to the Vaccine Adverse Event Reporting System (VAERS) reviewed and processed during December 22, 2020 — January 31, 2023; reported date of vaccination during December 22, 2020 — January 31, 2023 or missing Abara WE, et al. Expected Rates of Select Adverse Events After Immunization for Coronavirus Disease 2019 Vaccine Safety Monitoring | The Journal of Infectious Diseases ; Mahaux O, et al. Pharmacoepidemiological considerations in observed
‐to‐expected analyses for vaccines
CDC requests
medical records
34

          Reporting Rates of Death After mRNA*COVID-19 Vaccination Were Below
Background Rates of Death in the General U.S. Population
The most common causes of death reported to VAERS are consistent with the leading causes of death in the U.S. population
0 0.2 0.4 0.6 0.8 1 Observed/Expected Ratio 6 months-17 years 18-49 years 50-64 years 65+ years Observed / Expected <1: Indicates
lower observed death rate than
the expected rate within the post-
vaccination interval of 42 days
* Includes reports with missing vaccine type, but excludes reports known to be after Janssen or Novavax COVID-19 vaccine
Reports to the Vaccine Adverse Event Reporting System (VAERS) reviewed and processed during December 22, 2020 — January 31, 2023; reported date of vaccination during December 22, 2020 — January 31, 2023 or missing
Hoyert DL, Xu J. Deaths: preliminary data for 2011. Natl Vital Stat Rep. 2012; 61:1–51 ; U.S. Centers for Disease Control and Prevention. CDC WONDER. Available at https://wonder.cdc.gov/controller/datarequest/D157 Accessed March 20, 2025
Abara WE, et al. Expected Rates of Select Adverse Events After Immunization for Coronavirus Disease 2019 Vaccine Safety Monitoring | The Journal of Infectious Diseases ; Mahaux O, et al. Pharmacoepidemiological considerations in observed ‐to‐expected analyses for vaccines
National Center for Health Statistics, National Vital Statistics System. Deaths: Leading Causes of Death for 2021. 73:4. Published April 8, 2024. https://www.cdc.gov/nchs/data/nvsr/nvsr73/nvsr73-04.pdf National Center for Health Statistics, National Vital Statistics System. Deaths: Leading
Causes of Death for 2020. 72:13. Published December 5, 2023. https://www.cdc.gov/nchs/data/databriefs/db492-tables.pdf#4 35

       Data From CDC’s Vaccine Safety Datalink Shows No
Increased Risk of Death Following mRNA COVID-19 Vaccines
36 0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1
0.2 0.4 0.6 0.8 1 0.2 0.4 0.6 0.8 1 Dose 1 Dose 2
Non-COVID-19 mortality
All-cause mortality Cardiac-related mortality
Non-COVID-19 cardiac-related mortality
Non-COVID-19 mortality
All-cause mortality Cardiac-related mortality
Non-COVID-19 cardiac-related mortality
Non-COVID-19 mortality
All-cause mortality Cardiac-related mortality
Non-COVID-19 cardiac-related mortality
Non-COVID-19 mortality
All-cause mortality Cardiac-related mortality
Non-COVID-19 cardiac-related mortality Pfizer-BioNTech
Moderna Ages 12 Years and Older
Ages 65 Years and Older (Medicare Beneficiaries)
Dose 1 Dose 2
X axis: Relative Incidence and 95% Confidence Intervals Pfizer-BioNTech
Moderna •2 self-controlled case series
evaluations
•No increased risk in the 28 days
after vaccination of:
-Non-COVID mortality
-All-cause mortality
-Cardiac-related mortality
-Non-COVID cardiac-related mortality
•Similar findings in VSD cohort
study of people ages 12+ years
Mortality risk after COVID-19 vaccination: A self-controlled case series study
https://pubmed.ncbi.nlm.nih.gov/38388239/
A Modified Self-Controlled Case Series on Mortality Risk following Primary Series Doses of COVID-19
Vaccines in U.S. Medicare Beneficiaries Aged 65 Years and Older - Acumen and Vaccine Safety Datalink,
unpublished pending review at journal A safety study evaluating non-COVID-19 mortality risk following COVID-19 vaccination - PubMed
Data from December 14, 2020 through August 11, 2021

Tree-based data mining for safety assessment of first COVID-19 booster doses in the Vaccine Safety Datalink – PubMed
Safety signal identification for COVID-19 bivalent booster vaccination using tree-based scan statistics in the Vaccine Safety Datalink - PubMed
37 Using Data Mining to Assess for Unexpected
Events After COVID-19 Vaccination
• >60,000 possible adverse events assessed in the
70 day
s after vaccination using tree-based data
mining of ICD-10 codes in the VSD for:
-Primary series
-Initial booster
-Bivalent booster
• No new safety concerns identified outside of
known e
vents
-E.g., myocarditis/pericarditis, allergic reactions,
common local and systemic reactions
A broad assessment of covid-19 vaccine safety using tree-based data-mining in the vaccine safety datalink - PubMed
Summary
38
38

     CDC Summary: Adverse Events Associated with mRNA
COVID-19 Vaccines
Occur with any vaccines: Occur with COVID-19 vaccines:
• Local reactions • Myocarditis and pericarditis
• S
ystemic reactions
• Acute allergic reactions (e.g., anaphylaxis)
• Syncope (fainting)
• Shoulder injuries
CDC evaluated at least 65 specific safety outcomes, conducted data mining of
>60,000 potential outcomes for unexpected concerns, investigated numerous
signals, and conducted many epidemiologic studies
39

40 NASEM Consensus Report on Adverse
Effects of COVID-19 Vaccines – 2024
• Commissioned by Health Resources and Services
Administration (HRSA)
• Reviewed nearly 600 studies on safety of COVID-19 vaccines
• Concluded evidence supported causal association between mRNA COVID-19 vaccines and myocarditis
-Evidence favors rejection of causal relationship
between vaccination and 6 additional outcomes
Front Matter | Evidence Review of the Adverse Effects of COVID-19 Vaccination and Intramuscular Vaccine Administration |
The National Academies Press

        COVID-19 Vaccines Have Been Evaluated Under the Most
Extensive Safety Monitoring Program in U.S. History
• Safety surveillance identified and characterized the risk of myocarditis after mRNA
COVID-19 vaccination
• No other risks confirmed in the current U.S.-licensed vaccines except those seen with other vaccines (e.g., local and systemic reactions, allergic reactions)
• CDC continues to prioritize the monitoring of COVID-19 vaccine safety, with at least 30 ongoing studies or activities
• CDC continues to monitor the safety of COVID-19 vaccines
41

Summary: Update on CDC’s COVID-19 Vaccine Safety Monitoring  Sarah Meyer, MD MPH  Director, CDC’s Immunization Safety Office  June 25, 2025  1                                                                  Key Points  • CDC and interagency partners launched an extensive vaccine safety monitoring  program for COVID-19 vaccines  • Many potential safety outcomes were rigorously assessed through complementary passive and active systems  • Myocarditis is causally associated with mRNA COVID-19 vaccines …


05 Peacock COVID 508

COVID- 19 Vaccination ImplementationNational Center for Immunization and Respiratory Diseases
June 25, 2025Immunization Services Division
Centers for Disease Control and Prevention
•National Immunization Survey (NIS):
-Random -digit -dial cellular telephone survey of adults age ≥18 years in the U.S. (all
50 states, 5 local jurisdictions, and territories); all responses are self reported.
-Sample size: ~15,000 adult respondents weekly, ~60,000 adult respondents monthly
-Data are weighted to represent the non- institutionalized U.S. population
•Immunization Information Systems (IISs):
-Confidential, population- based databases that record all vaccine doses administered
by participating providers in a specific geographic area
-ISD receives monthly aggregate data for COVID, influenza, and RSV, and quarterly
line-level, de -identified data for individual immunizations
•Vaccine Safety Datalink:
-Estimates of vaccination coverage are based on electronic health data from multiple integrated health systemsData sources used to estimate U.S. immunization
coverage
COVID -19 Vaccination Coverage
National Immunization Survey -Fall Respiratory Virus Module
0.020.040.060.08
0.0
9/7/2024
9/14/2024
9/21/20249/28/202410/5/2024
10/12/2024
10/19/2024
10/26/2024
11/2/202411/9/2024
11/16/2024
11/23/2024
11/30/2024
12/7/2024
12/14/2024
12/21/2024
12/28/2024
1/4/2025
1/11/20251/18/20251/25/2025
2/1/20252/8/2025
2/15/20252/22/2025
3/1/20253/8/2025
3/15/20253/22/20253/29/2025
4/5/2025
4/12/20254/19/20254/26/2025Vaccination coverage (%)
Week ending date≥1 dose (65+)
≥1 dose (18+)COVID -19 V accination Coverage (≥1 Dose) Among Adults 18 Years and Older
and 65 Years and Older , 2024- 2025
National Immunization Survey -Fall Respiratory Virus Module
44.1
23.0
0255075100
Sep 7
Sep 14
Sep 21Sep 28
Oct 5
Oct 12Oct 19Oct 26
Nov 2Nov 9
Nov 16Nov 23Nov 30
Dec 7
Dec 14Dec 21Dec 28
Jan 4
Jan 11Jan 18Jan 25
Feb 1Feb 8
Feb 15Feb 22
Mar 1Mar 8
Mar 15Mar 22Mar 29
Apr 5
Apr 12Apr 19Apr 26
Sep 7
Sep 14Sep 21Sep 28
Oct 5
Oct 12Oct 19Oct 26
Nov 2Nov 9
Nov 16Nov 23Nov 30
Dec 7
Dec 14Dec 21Dec 28
Jan 4
Jan 11Jan 18Jan 25
Feb 1Feb 8
Feb 15Feb 22
Mar 1Mar 8
Mar 15Mar 22Mar 29
Apr 5
Apr 12Apr 19Apr 26
Sep 7
Sep 14Sep 21Sep 28
Oct 5
Oct 12Oct 19Oct 26
Nov 2Nov 9
Nov 16Nov 23Nov 30
Dec 7
Dec 14Dec 21Dec 28
Jan 4
Jan 11Jan 18Jan 25
Feb 1Feb 8
Feb 15Feb 22
Mar 1Mar 8
Mar 15Mar 22Mar 29
Apr 5
Apr 12Apr 19Apr 26≥18 years 65-74 years ≥75 yearsVaccination coverage (%)
2024- 25 season week ending dateVaccination coverage (2024-25) Vaccination coverage (2023-24)COVID -19 Vaccination Coverage Among Adults ≥18 Years, 65 -74 Years,
and ≥75 Years, 2023 -24 and 2024 -25
National Immunization Survey -Fall Respiratory Virus Module
23.0
21.
642.7
37.946.5
38.3
0255075100Vaccination coverage (%)
Week ending dateOverall (6 months-17 years) 6 months-4 years 5-11 years 12-17 yearsCOVID -19 Vaccination Coverage* Among Children 6 Months –17 Years of
Age, October 2024 –April 2025, NIS -Flu
* Up -to-date with the updated 2024 –25 COVID -19 vaccine is defined as receipt of at least one vaccination since August 22, 2024, for children ≥5 years; for children <5 years, up -to-
date status was defined based on the current recommendations that also take into account number of doses and brand of vaccine. Up- to-date status was determined by survey
questions on month and year of most recent COVID- 19 vaccine, and for children <5 years, total number of COVID -19 vaccinations re ceived and brand of most recent COVID- 19
vaccine.
COVID -19 V accination Coverage (≥2 Doses) Among Adults 18 Years and Older
Who Are Immunocompromised Who Received First Dose in August/September
2024, as of End of March 2025
National Immunization Survey -Fall Respiratory Virus Module
*Immunocompromised a dults  were recommended to receive a second dose of 2024 -2025 COVID- 19 vaccine
six months after their first dose .2.416.60.81.49.98.1
0.0 10.0 20.0 30.0 40.0 50.0 60.018-49 (n=85)50-64 (n=98)65+ (n=172)Male (n=95)Female (n=257)Overall 18+ immun
ocompromised
(n=355)
Weig
hted % (95% CI)
•COVID -19 vaccination coverage for older adults improved in 2024-2025
compared to the previous season, but vaccination coverage for all adults >
18 years was similar between the 2023-2024 and 2024-2025 seasons.
•Approximately 13% of children between 6 months and 17 years of age
were up to date with COVID vaccination at the end of April 2025. Summary
For more information, contact CDC/ATSDR
1-800- CDC- INFO (232- 4636)
TTY:  1 -888- 232- 6348    www.cdc.gov           www.atsdr.cdc.gov
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention and the Agency for Toxic Substances and Disease Registry.
Thank you

Summary: COVID- 19 Vaccination ImplementationNational Center for Immunization and Respiratory Diseases June 25, 2025Immunization Services Division Centers for Disease Control and Prevention •National Immunization Survey (NIS): -Random -digit -dial cellular telephone survey of adults age ≥18 years in the U.S. (all  50 states, 5 local jurisdictions, and territories); all responses are self reported. -Sample size: ~15,000 adult respondents weekly, ~60,000 adult respondents monthly -Data are weighted to…


06 MacNeil COVID 508

Evidence to Recommendations (partial) for 2025 –2026
COVID -19 Vaccination
Coronavirus and Other Respiratory Viruses Division
June 25, 2025National Center for Immunization and Respiratory Diseases
1
Evidence to Recommendations ( EtR) Framework
EtR Domain Question(s)
Public Health Problem •Is the problem of public health importance?
Benefits and Harms•How substantial are the desirable anticipated effects?
•How substantial are the undesirable anticipated effects?
•Do the desirable effects outweigh the undesirable effects?
Values•Does the target population feel the desirable effects are large relative
to the undesirable effects?
•Is there important variability in how patients value the outcome?
Acceptability •Is the intervention acceptable to key stakeholders?
Feasibility •Is the intervention feasible to implement?
Resource Use •Is the intervention a reasonable and efficient allocation of resources?
Equity •What would be the impact of the intervention on health equity?
•May 29th work group call
-Public Health Problem domain of the Evidence to Recommendations ( EtR)
Framework was presented
•June 5th work group call
-Benefits and Harms domain of the EtR was presented
•June 12th planned work group call
-Additional EtR domains were planned to be presented
-Final work group polling not completed because call was not convenedWork Group Interpretations
3
Summary
Public Health Problem
•Burden from COVID -19 has been trending down year over year since 2021, but
substantial morbidity and mortality continues to occur.
•Higher rates of COVID -19 hospitalization and deaths occur in the oldest and
youngest age groups.
-Highest rates in adults ages ≥65 years and infants ages <6 months
•Children ages <2 years have the highest morbidity and mortality of all pediatric ages,
but deaths due to COVID -19 can occur at any age.
-Maternal vaccination is the best protection against COVID -19 for pregnant women
and infants less than 6 months of age (who are too young to be vaccinated).
•2024 –2025 COVID -19 vaccination is effective in preventing hospitalizations and critical
outcomes from COVID -19 in adults.
-Data from prior vaccine formulations show that vaccine effectiveness has been similar
across age groups.
•COVID -19 vaccines have been continuously monitored through robust safety surveillance
•Safety surveillance identified and characterized the risk of myocarditis and pericarditis
after mRNA COVID -19 vaccination.
-No other risks confirmed in the current U.S. -licensed vaccines except those seen with
other vaccines (e.g., local and systemic reactions, allergic reactions).
•Pregnant women are at increased risk of severe disease and adverse pregnancy outcomes
from COVID -19.
•Maternal vaccination has been shown to protect infants <6 months of age from severe
outcomes of COVID -19.Summary
Benefits and Harms
Thank you to all the CDC and external collaborators who
contributed to these presentations.

Summary: Evidence to Recommendations (partial) for 2025 –2026  COVID -19 Vaccination Coronavirus and Other Respiratory Viruses Division June 25, 2025National Center for Immunization and Respiratory Diseases 1 Evidence to Recommendations ( EtR) Framework EtR Domain Question(s) Public Health Problem •Is the problem of public health importance? Benefits and Harms•How substantial are the desirable anticipated effects? •How substantial are the undesirable anticipated effects? •Do the desirable effects…


01 MacNeil Mat Peds RSV 508

Maternal/Pediatric Respiratory Syncytial Virus (RSV)
Session
Advisory Committee on Immunization Practices Meeting
June 25, 2025
1U.S. Centers for Disease Control and Prevention
Session Introduction
•RSV can infect the small airways in the lungs,
particularly in infants
•Most (68%) infants are infected in the first year of
life and nearly all (97%) by age 2 years2
•2-3% of young infants are hospitalized for RSV3,4,5
-~80% of children hospitalized with RSV age <2 years
have no underlying medical conditions3
•Prior to 2023, no long -acting* products were
available for the prevention of severe RSV disease
*Long -acting is defined as any product that requires one dose to provide protection during an RSV season
References: 1) Suh et al, JID (2022): https://doi.org/10.1093/infdis/jiac120  2) Glezen  et al, Arch Dis Child (1986): https://doi.org/10.1001/archpedi.1986.02140200053026  3) Hall
et al, Pediatrics (2013): https://doi.org/10.1542/peds.2013 -0303  4) Langley et al, PIDJ (2011): https://doi.org/10.1097/INF.0b013e3182184ae7  5) Curns et al, Pediatric s (2024):
https://doi.org/10.1542/peds.2023 -062574RSV is the leading cause of hospitalization in U.S. infants1
Image: Goncalves et al. Critical Care
Research and Practice 2012
2
In 2023 two products were approved by FDA and subsequently
recommended by CDC and ACIP
Maternal RSV
vaccine
Abrysvo, Pfizer
*Either  maternal RSV vaccine or nirsevimab is given to protect infants against severe RSV disease
– only one is needed in most instances
Pregnant women 32 through
36 weeks’ gestation
Administer September
through January in most of
thecontinental United
States†All infants ages <8 months*
Second season dose for children
ages 8 –19 months at increased
risk of severe RSV disease
Administer October through
March in most of the continental
United States†(as early as
possible¥)
† Timing of administration for RSV immunization may differ in jurisdictions with RSV seasonality that differs from most of th e continental United States; ¥ The optimal timing for nirsevimab
administration is shortly before the RSV season begins (e.g., October –November), or within a baby's first week of life if born O ctober through March (ideally during the birth hospitalization.)Nirsevimab
Beyfortus , Sanofi & AstraZeneca
3
Today the committee will be considering a recommendation
for a newly FDA -approved product
Maternal RSV
vaccine
Abrysvo, Pfizer
*Either  maternal RSV vaccine or an infant antibody is given to protect infants against severe RSV
disease – only one is needed in most instances
Pregnant women
32 through 36
weeks’ gestation
Administer
September through
January in most of
thecontinental
United States†All infants ages <8
months*
Second season dose for
children ages 8 –19
months at increased risk
of severe RSV disease
Administer October
through March in most of
the continental United
States † (as early as
possible¥)Nirsevimab
Beyfortus , Sanofi &
AstraZeneca Clesrovimab
Enflonasia , Merck
Approved by FDA on
6/9/2025
All infants ages <8
months*
Administer October
through March in most of
the continental United
States † (as early as
possible¥)
† Timing of administration for RSV immunization may differ in jurisdictions with RSV seasonality that differs from most of th e continental United States; ¥ The optimal timing for nirsevimab
administration is shortly before the RSV season begins (e.g., October –November), or within a baby's first week of life if born O ctober through March (ideally during the birth hospitalization.)4
•September 2024 : Maternal/pediatric RSV work group reviewed and discussed data from Merck on
safety and efficacy of clesrovimab
•October 2024: ACIP reviewed and discussed data from Merck on safety and efficacy of clesrovimab
and the maternal/pediatric work group’s interpretation of these data
•November 2024 – April 2025: Maternal/Pediatric RSV work group reviewed and discussed
-GRADE1,2 (Grading of Recommendations, Assessment, Development, and Evaluations) for
clesrovimab
-Evidence to Recommendation Framework2 for clesrovimab
•April 2025: ACIP reviewed and discussed the Evidence to Recommendation Framework and GRADE
for clesrovimab
•June 2025 (Today): ACIP will be presented with recap of the Evidence to Recommendations
Framework and vote on clesrovimabTimeline of work group and ACIP review of clesrovimab
References : 1) Ahmed et al, Vaccine (2011 ): https://doi.org/10.1016/j.vaccine.2011.08.005  2) Lee et al, MMRW (2018): https://www.cdc.gov/mmwr/volumes/67/wr/mm6745a4.htm  5
•April – June 2025: The work group reviewed data on uptake, safety, and
effectiveness of maternal RSV vaccine and long -acting monoclonal antibody
from the 2024 -2025 season
•June 2025 (Today): ACIP will be presented with these data as well as the
work group interpretationAdditional data reviewed by the work group since the
April 2025 ACIP meeting
6
•Updates on administration and uptake of maternal RSV vaccine and long -acting
monoclonal antibody — Dr. Georgina Peacock (CDC/NCIRD)
•Updates on effectiveness and impact of maternal RSV vaccine and long -acting monoclonal
antibody — Dr. Adam MacNeil (CDC/NCIRD)
•Safety of maternal RSV vaccine and long -acting monoclonal antibody — Dr. Malini DeSilva
(HealthPartners Institute) & Dr. Matthew F. Daley (Kaiser Permanente Institute for Health
Research)
•Evidence to Recommendation Framework: Clesrovimab — Dr. Adam MacNeil (CDC/NCIRD)
•Clinical considerations and work group interpretation — Dr. Adam MacNeil (CDC/NCIRD)Today’s agenda: June 25, 2025
7
For more information, contact CDC
1-800-CDC-INFO (232 -4636)
TTY:  1 -888-232-6348    cdc.gov
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position
of the U.S. Centers for Disease Control and Prevention.
Thank you

Summary: Maternal/Pediatric Respiratory Syncytial Virus (RSV)  Session Advisory Committee on Immunization Practices Meeting June 25, 2025 1U.S. Centers for Disease Control and Prevention Session Introduction •RSV can infect the small airways in the lungs,  particularly in infants •Most (68%) infants are infected in the first year of  life and nearly all (97%) by age 2 years2 •2-3% of young infants are hospitalized for RSV3,4,5 -~80% of children hospitalized with RSV age <2 years  have no underlying…