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Interim Estimates of 2024 -2025 COVID -19
Vaccine Effectiveness
Ruth Link -Gelles, PhD, MPH
CDR, US Public Health Service
Coronavirus and Other Respiratory Viruses Division
Centers for Disease Control and Prevention
April 15, 2025National Center for Immunization and Respiratory Diseases
2•Context for interpretation of VE
•2024 -2025 COVID -19 vaccine coverage
•Vaccine effectiveness methods
•Interim 2024 -2025 COVID -19 vaccine effectiveness Agenda –COVID -19 vaccine effectiveness (VE)
3•High rates of SARS -CoV-2 infection -induced immunity by October –December 2023.*Context for interpreting COVID -19 VE across age groups: high infection -
induced seroprevalence by end of 2023
* Data on persons aged ≥16 years from a longitudinal, national cohort of ~35,000 blood donors.
Methods and data available at: 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
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.
4COVID -19 Vaccination Coverage Among Adults ≥18 Years, 65 -74 Years,
and ≥75 Years, 2023 and 2024, NIS -ACM
0255075100
Sep 7
Sep 14
Sep 21
Sep 28
Oct 5
Oct 12
Oct 19
Oct 26
Nov 2
Nov 9
Nov 16
Nov 23
Nov 30
Dec 7
Dec 14
Dec 21
Dec 28
Sep 7
Sep 14
Sep 21
Sep 28
Oct 5
Oct 12
Oct 19
Oct 26
Nov 2
Nov 9
Nov 16
Nov 23
Nov 30
Dec 7
Dec 14
Dec 21
Dec 28
Sep 7
Sep 14
Sep 21
Sep 28
Oct 5
Oct 12
Oct 19
Oct 26
Nov 2
Nov 9
Nov 16
Nov 23
Nov 30
Dec 7
Dec 14
Dec 21
Dec 28
Adults ≥18 years Adults 65-74 years Adults ≥75 yearsVaccination coverage (%)
Week endingCOVID-19 vaccination coverage (2024) COVID-19 vaccination coverage (2023)
Slide courtesy of CDC Immunization Services Division.
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.
Methods
5
6Measuring COVID -19 vaccine effectiveness
Measure Definition Example
vaccinated
groupExample comparison group
Absolute VE Compares frequency of health
outcomes in vaccinated and
unvaccinated people Received
original
monovalent
COVID -19
vaccineReceived 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
COVID -19
vaccineEligible for, but did not receive, bivalent
COVID -19 vaccine , but received
original monovalent COVID -19
vaccine
VE of 2024 -2025 COVID -
19 vaccines*Compares people who received
2024 -2025 COVID -19 vaccine to
people who did not, regardless
of past vaccinationReceived
2024 -25 doseEligible for, but did not receive, an
2024 -25 dose , regardless of past
vaccination history
*Vaccine effectiveness was also measured this way for 2023 -2024 COVID -19 vaccines
7VISION Multi -Site Network of Electronic Health Records
>300 emergency departments and urgent cares and >200 hospitals
▪Design: Test-negative design
▪Population: Adults ≥18 years visiting a participating
emergency department or urgent care (ED/UC) or
hospitalized with COVID -19-like illness (CLI) 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. Link -Gelles, et al. In press, MMWR.
8IVY Network —26 hospitals, 20 U.S. States
•Design : Test-negative, case -control design
•Population : Adults aged ≥65 years hospitalized with COVID -
like illness (CLI)* 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 and
RSV by RT -PCR
•Vaccination data: Electronic medical records (EMR), state and
city registries, and plausible self -report
•Specimens: Nasal swabs obtained on all patients for central
RT-PCR testing and whole genome sequencing
*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
Interim Estimates of 2024 -2025 COVID -19
Vaccine Effectiveness
9
10Characteristics 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 –January 2025
CharacteristicVaccine effectiveness network and setting, no. (column %)
VISION
ED/UC encounters,
all adults aged ≥18 yearsVISION
hospitalizations,
all adults aged ≥65 yearsIVY
hospitalizations,
immunocompetent 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 137,543 10,459 127,084 34,411 2,846 31,565 1,929 683 1,246
Median age 53 [34, 72] 58 [37, 74] 53 [34, 71] 78 [72, 84] 79 [73, 86] 78 [71, 84] 77 [71, 84] 78 [72, 85] 76 [70, 83]
Age group
18-64 years 88,858 (65) 6,113 (58) 82,745 (65) -- -- -- -- --
≥65 years 48,685 (35) 4,346 (42) 44,339 (35) 34,411 (100) 2,846 (100) 31,565 (100) 1,929 (100) 683 (100) 1,246 (100)
Immunocompromised* -- -- -- 8,192 (24) 598 (21) 7,594 (24) -- --
Link-Gelles, et al. MMWR: https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm
ED/UC = emergency department/urgent care
* Immunocompromised status is not evaluated for ED/UC encounters due to a higher likelihood of incomplete discharge diagnosis codes in this setting.
11Effectiveness of 2024 –2025 COVID -19 vaccination against COVID -19–associated emergency
department/urgent care encounters by age group — VISION Network
September 2024 – January 2025
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. The odds ratio was adjusted for age, sex, race and ethnicity, calendar d ay, and geographic region. 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 (if any) received.
* Time since vaccination is for most recent 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) 9,545 (91) 108,972 (86) 998 (539 -1,142) Ref
Received 2024 -2025 COVID -19 dose 7–119 days earlier 914 (9) 18,112 (14) 55 (32 -80) 33 (28 -38)
2024 -2025 COVID -19 dose , 7–59 days earlier 480 (5) 9,789 (8) 33 (20 -46) 36 (29 -42)
2024 -2025 COVID -19 dose , 60–119 days earlier 434 (4) 8,323 (7) 82 (71 -97) 30 (22 -37)
18-64 years
No 2024 -2025 COVID -19 dose (Ref) 5,860 (96) 76,792 (93) 1,042 (751 -1,180) Ref
Received 2024 -2025 COVID -19 dose 7–119 days earlier 253 (4) 5,953 (7) 53 (29 -77) 30 (20 -39)
2024 -2025 COVID -19 dose , 7–59 days earlier 134 (2) 3,379 (4) 32 (20 -45) 36 (23 -46)
2024 -2025 COVID -19 dose , 60–119 days earlier 119 (2) 2,574 (3) 81 (70 -95) 21 (5 -35)
≥65 years
No 2024 -2025 COVID -19 dose (Ref) 3,685 (85) 32,180 (73) 750 (346 -1,076) Ref
Received 2024 -2025 COVID -19 dose 7–119 days earlier 661 (15) 12,159 (27) 57 (33 -82) 35 (29 -41)
2024 -2025 COVID -19 dose , 7–59 days earlier 346 (8) 6,410 (14) 34 (21 -47) 36 (28 -44)
2024 -2025 COVID -19 dose , 60–119 days earlier 315 (7) 5,749 (13) 83 (71 -97) 34 (25 -42)
0 20 40 60 80 100
Vaccine effectiveness (%)
12Effectiveness of 2024 –2025 COVID -19 vaccination against COVID -19–associated hospitalization
among immunocompetent adults aged ≥65 years — VISION and IVY Networks
September 2024 – January 2025
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)
VISION
No 2024 -2025 COVID -19 dose (Ref) 2,016 (90) 19,198 (80) 775 (357 -1,084) Ref
Received 2024 -2025 COVID -19 dose 7–119 days earlier 232 (10) 4,773 (20) 53 (30 -77) 45 (36 -53)
2024 -2025 COVID -19 dose , 7–59 days earlier 129 (6) 2,759 (12) 33 (20 -46) 42 (30 -52)
2024 -2025 COVID -19 dose , 60–119 days earlier 103 (5) 2,014 (8) 81 (70 -94) 48 (36 -58)
IVY
No 2024 -2025 COVID -19 dose (Ref) 614 (90) 1,021 (82) Not available Ref
Received 2024 -2025 COVID -19 dose 7–119 days earlier 69 (10) 225 (18) 60 (31 –85) 46 (26 -60)
2024 -2025 COVID -19 dose , 7–59 days earlier 41 (6) 105 (9) 31 (20 –45) 42 (14 -61)
2024 -2025 COVID -19 dose , 60–119 days earlier 28 (4) 120 (11) 85 (72 –98) 47 (17 -67)
0 20 40 60 80 100
Vaccine effectiveness (%)
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.
*Time since vaccination is for most recent dose, which could have been an original monovalent, bivalent, 2023 -2024, or 2024 -2025 COVID -19 vaccine.
13Effectiveness of 2024 –2025 COVID -19 vaccination against COVID -19–associated hospitalization
among immunocompromised adults aged ≥65 years — VISION
September 2024 – January 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 VE (95% CI)
VISION
No 2024 -2025 COVID -19 dose (Ref) 524 (88) 5,885 (78) 720 (343 -1,064) Ref
Received 2024 -2025 COVID -19 dose 7–119 days earlier 74 (12) 1,709 (22) 53 (31 -78) 40 (21 -54)
0 20 40 60 80 100
Vaccine effectiveness (%)
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. 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 COVI D-19 vaccine doses (if any) received.
* Time since vaccination is for most recent dose, which could have been an original monovalent, bivalent, 2023 -2024, or 2024 -2025 COVID -19 vaccine.
14•2024 -2025 COVID -19 vaccination provided additional protection against COVID -19-associated emergency
department and urgent care visits and hospitalizations compared to no 2024 -2025 vaccine dose.
•2024 -2025 COVID -19 vaccination also provided additional protection against COVID -19-associated
hospitalizations among adults aged ≥65 years with immunocompromising conditions.
•VE should be interpreted as the added benefit of 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 have resulted in lower measured VE than in a population with less
recent infection.Conclusions: effectiveness of 2024 -2025 COVID -19
vaccines
15Acknowledgements
CDC
Amanda B. Payne
Lakshmi Panagiotakopoulos
Lauren Roper
Diya Surie
Amadea Britton
Allison Ciesla
Fatimah Dawood
Jennifer DeCuir
Shikha Garg
Amber Kautz
Nathaniel M. Lewis
Josephine Mak
Morgan Najdowski
Caitlin Ray
Emily Reeves
Alexander Webber
Ryan WiegandVISION Collaborators
Westat
Sarah Ball
Angela Cheung
Sean Chickery
Patrick Mitchell
Sarah Reese
Elizabeth Rowley
Janet Watts
Zack Weber
Intermountain Health
Kristin Dascomb
Kaiser Permanente Center for Health Research
Stephanie A. Irving
Kaiser Permanente Northern California
Nicola P. Klein
Regenstrief
Shaun J. Grannis
University of Colorado
Toan C. Ong
HealthPartners
Malini B. DeSilva
Columbia University
Karthik NatarajanIVY Collaborators
Wesley H. Self
Yuwei Zhu
Adam S. Lauring
Emily T. Martin
Ithan D. Peltan
Adit A. Ginde
Nicholas M. Mohr
Kevin W. Gibbs
David N. Hager
Matthew E. Prekker
Amira Mohamed
Nicholas Johnson
Jay S. Steingrub
Akram Khan
Jamie R. Felzer
Abhijit Duggal
Jennifer G. Wilson
Nida Qadir
Christopher Mallow
Jennie H. Kwon
Cristie Columbus
Ivana A. Vaughn
Basmah Safdar Jarrod M. Mosier
Estelle S. Harris
James D. Chappell
Natasha Halasa
Cassandra Johnson
+ many more!