cdc.gov/coronavirus

Updates on COVID-19 Vaccine 

Effectiveness during Omicron

Ruth Link-Gelles, PhD, MPH

LCDR, US Public Health Service

Program Lead, COVID-19 Vaccine Effectiveness

National Center for Immunization and Respiratory Diseases

ACIP

September 1, 2022
▪ Presentation organized by outcome, then by age within outcome

– Infection

– Emergency department/urgent care (ED/UC)

– Hospitalization

Organization of presentation

2
Vaccine effectiveness (VE) against 

infection with Omicron
▪ Nationwide community-based drive-through COVID-19 testing via pharmacies

▪ Self-reported vaccine history at time of registration for COVID-19 testing; 

excluded those who did not report vaccination status

▪ Design: Test-negative, case-control analysis

▪ Population: Persons with ≥1 COVID-like symptom and nucleic acid 

amplification testing (NAAT); immunocompromised excluded

▪ Adjusted for:

– Race, ethnicity, gender, patient state, site census tract’s social vulnerability index (SVI), circulating cases 

of COVID-19 by zip code in the last 7 days, pharmacy partner, test date 

▪ Period for analysis: 

– Tested: July 2, 2022 – August 20, 2022, BA.4/BA.5 predominant period

Increasing Community Access to Testing (ICATT) 

Partnership: VE analysis for symptomatic infection
ICATT: mRNA 3 vs. 2-dose relative VE against symptomatic 

infection during BA.4/BA.5, ages 5+ years

5

*Vaccination dose dates are collected as month and year. Month 0 represents tests in the same month as last dose (at least 2 weeks after last dose). For all months greater 

than or equal to 1 the value represents the difference between calendar month of test and calendar month of last dose receipt (at least 2 weeks after last dose).

CDC preliminary unpublished data. Prior infection excluded, other methods based on: Fleming-Dutra KE, Britton A, Shang N, et al. Association of Prior BNT162b2 COVID-19 Vaccination With 

Symptomatic SARS-CoV-2 Infection in Children and Adolescents During Omicron Predominance. JAMA. Published online May 13, 2022. doi:10.1001/jama.2022.7493

-40%

-20%

0%

20%

40%

60%

80%

100%

0 1 2 3 4 5 6 7 8

Vaccine Effectiveness

*Months since last dose

05-11yo VE

12-15yo VE

16-49yo VE

50-64yo VE

65+yo VE
-20%

0%

20%

40%

60%

80%

100%

0 1 2 3 4

Vaccine Effectiveness

*Months since last dose

-20%

0%

20%

40%

60%

80%

100%

0 1 2 3 4

Vaccine Effectiveness

*Months since last dose

3 vs. 0-dose absolute VE 4 vs. 3-dose relative VE

6

*Vaccination dose dates are collected as month and year. Month 0 represents tests in the same month as last dose (at least 2 weeks after last dose). For all months greater 

than or equal to 1 the value represents the difference between calendar month of test and calendar month of last dose receipt (at least 2 weeks after last dose).

50-64 years

65+ years

95% CIs

CDC preliminary unpublished data. Prior infection excluded, other methods based on: Fleming-Dutra KE, Britton A, Shang N, et al. Association of Prior BNT162b2 COVID-19 Vaccination With 

Symptomatic SARS-CoV-2 Infection in Children and Adolescents During Omicron Predominance. JAMA. Published online May 13, 2022. doi:10.1001/jama.2022.7493

ICATT: mRNA VE against symptomatic infection during 

BA.4/BA.5, ages 50+ years
Vaccine effectiveness against emergency 

department/urgent care (ED/UC) due to 

Omicron in the US
VISION Multi-State Network of Electronic Health Records

▪ Delta vs. Omicron determined by 

time when Omicron predominated in 

study site (mid-December 2021)

▪ VE adjusted by propensity to be 

vaccinated weights, calendar time, 

region, local virus circulation, and 

age

▪ Vaccination documented by 

electronic health records and state 

and city registries

▪ Cases: COVID-like illness (CLI) with positive 

PCR for SARS-CoV-2 within 14 days before 

or 72 hours after the admission or encounter

▪ Controls: CLI with negative PCR for SARSCoV-2
VISION: Pfizer-BioNTech VE for ED/UC visits by number of doses and time since last dose 

receipt for children and adolescents during Omicron, mid-Dec 2021–mid-Jul 2022

CDC, preliminary unpublished data. Individuals with prior infections excluded. Adjusted for calendar time, geographic region, age, sex, race, ethnicity, local virus circulation, respiratory or nonrespiratory underlying medical conditions, and propensity to be vaccinated

COVID-like illness: included acute respiratory illness (e.g., COVID-19, respiratory failure, or pneumonia) or related signs or symptoms (cough, fever, dyspnea, vomiting, or diarrhea)

9

Vaccination status 

(days since most recent 

dose)

Total SARS-CoV-2

positive, N

Adjusted

VE (95% CI)

5-11 years

Unvaccinated 21,009 1,375 Ref

2 doses (14-59) 1,151 72 51 (34-64)

2 doses (60-149) 4,068 179 22 (6-36)

2 doses (≥150) 1,338 109 18 (-4-35)

12-15 years

Unvaccinated 7,318 1,443 Ref

2 doses (14-59) 219 27 60 (37-74)

2 doses (60-149) 1,082 196 42 (30-53)

2 doses (≥150) 3,308 587 14 (2-24)

3 doses (≥7) 973 43 63 (48-73)

-20 0 20 40 60 80 100

Vaccine Effectiveness (%)

2-dose VE

3-dose VE
Vaccination status 

(days since most 

recent dose) Total CLI cases

Days since most recent 

dose, median (IQR)

Adjusted VE

% (95% CI)

BA.2/BA.2.12.1 period

Unvaccinated 27,907 3,501 Ref.

2 doses (14-149) 1,774 110 104 (71, 128) 51 (38 - 60)

2 doses (≥150) 20,883 2,584 352 (278, 398) 12 (7 - 17)

3 doses (7-119) 9,142 441 94 (72, 108) 56 (51 - 61)

3 doses (≥120) 26,654 3,186 166 (145, 190) 26 (21 - 30)

4 doses (7-59)* 4,092 355 28 (17-42) 66 (60 - 71)

BA.4/BA.5 period

Unvaccinated 22,867 6,717 Ref.

2 doses (14-149) 540 82 106 (70, 133) 44 (28 - 56)

2 doses (≥150) 15,614 3,686 420 (321, 465) 26 (22 - 30)

3 doses (7-119) 1,280 154 77 (45, 100) 59 (50 - 66)

3 doses (≥120) 18,803 4,063 223 (193, 252) 33 (29 - 37)

4 doses (7-59)* 2,169 259 39 (24, 49) 62 (54 - 68)

4 doses (60-119)* 3,741 617 85 (74, 91) 49 (41 - 56)

VISION: mRNA VE for ED/UC visits among immunocompetent adults ≥18 years by 

number of doses and time since last dose receipt, late-Mar–late-Jul 2022

BA.2/BA.2.12.1 estimates: Link-Gelles et al. MMWR: https://www.cdc.gov/mmwr/volumes/71/wr/mm7129e1.htm

BA.4/BA.5 estimates: CDC, preliminary unpublished data. Individuals with prior infections excluded. Adjusted for calendar time, geographic region, age, sex, race, ethnicity, local virus circulation, respiratory or nonrespiratory underlying medical conditions, and propensity to be vaccinated. 

10

0 20 40 60 80 100

Vaccine Effectiveness (%)

* Only estimated among adults ≥50 years of age

2-dose VE

3-dose VE

4-dose VE
▪ Platform: Cosmos is an opt-in database of more than 162 million patient records 

drawn from health care organizations using the Epic platform for electronic health 

records

▪ Design: test-negative, case-control analysis

▪ Period: early April 2022 through mid-August 2022

▪ Population: immunocompetent children and adolescents ages 5–15 years

▪ Methods: 

– Cases: COVID-like illness with positive SARS-CoV-2 NAAT within 14 days before or 3 days after the 

encounter

– Controls: COVID-like illness with negative SARS-CoV-2 NAAT within 14 days before or 3 days after the 

encounter

– VE estimated using unconditional logistic regression; cases and controls frequency matched by 2-week 

period and state

– adjusted for race, ethnicity, sex, influenza vaccination status, number of underlying conditions

Cosmos Multi-State Network of Electronic Health 

Records
Cosmos: mRNA VE for ED/UC visits among children and adolescents by number 

of doses and time since last dose during Omicron predominance (combined 

BA.2/2.12.1/4/5 period) April 2022– mid-August 2022

CDC, preliminary unpublished data. 12

Vaccination status (days since 

most recent dose) Total SARS-CoV-2 positive, N (%) Adjusted VE % (95% CI)

5-11-year-olds

Unvaccinated 74,710 15,148 (20.3) REF

2 doses (14-120 days) 1,591 186 (11.7) 48 (39-55)

2 doses (≥120 days) 3,674 679 (18.5) 11 (3-18)

3 doses (14-120 days) 195 21 (10.8) 52 (27-71)

12-15-year-olds

Unvaccinated 28,722 6,022 (21) REF

2 doses (14-120 days) 443 37 (8) 65 (52-76)

2 doses (≥120 days) 4,359 736 (17) 21 (14-28)

3 doses (7-120 days) 687 64 (9) 60 (48-69)

3 doses (≥120 days) 524 88 (17) 18 (-3-36)

0 20 40 60 80 100

Vaccine Effectiveness (%)

2-dose VE

3-dose VE
Vaccine effectiveness against 

hospitalization due to Omicron in the US
Vaccination status 

(days since most 

recent dose) Total CLI cases

Days since most recent 

dose, median (IQR)

Adjusted VE

% (95% CI)

BA.2/BA.2.12.1 period

Unvaccinated 6,682 494 Ref.

2 doses (14-149) * * * *

2 doses (≥150) 5,118 393 371 (308, 413) 24 (12 - 35)

3 doses (7-119) 2,350 72 94 (74, 108) 69 (58 - 76)

3 doses (≥120) 7,686 519 168 (146, 191) 52 (44 - 59)

4 doses (7-59)** 1,204 74 27 (17, 41) 80 (71 - 85)

BA.4/BA.5 period

Unvaccinated 4,578 913 Ref.

2 doses (14-149) * * * *

2 doses (≥150) 3,592 619 445 (369, 484) 25 (15 - 33)

3 doses (7-119) 335 32 76 (46, 100) 49 (20 - 68)

3 doses (≥120) 5,030 869 229 (199, 256) 34 (25 - 42)

4 doses (7-59)** 717 81 38 (23, 49) 60 (42 - 73)

4 doses (60-119)** 1,146 157 84 (73, 97) 56 (41 - 67)

VISION: mRNA VE for hospitalizations among immunocompetent adults ≥18 years 

by number of doses and time since last dose receipt, late-Mar–late-Jul 2022

BA.2/BA.2.12.1 estimates: Link-Gelles et al. MMWR: https://www.cdc.gov/mmwr/volumes/71/wr/mm7129e1.htm 

BA.4/BA.5 estimates: CDC, preliminary unpublished data. Individuals with prior infections excluded. Adjusted for calendar time, geographic region, age, sex, race, ethnicity, local virus circulation, respiratory or nonrespiratory underlying medical conditions, and propensity to be vaccinated. 

14

0 20 40 60 80 100

Vaccine Effectiveness (%)

* Estimates with confidence intervals >50 percentage points are not shown.

** Only estimated among adults ≥50 years of age

2-dose VE

3-dose VE

4-dose VE
15

IVY Network: VE against Omicron variant COVID-19-associated 

hospitalization

▪ Design: Test-negative, case-control assessment

▪ Period: December 26, 2021–July 31, 2022

▪ Population: Adults (≥18 years) hospitalized at 21 

medical centers in 18 states

▪ Participants have COVID-like illness and test:

– Cases: SARS-CoV-2-positive by RT-PCR or antigen tests

– Controls: SARS-CoV-2-negative by RT-PCR

▪ VE adjustments: 

– Age (18–49, 50–64, and ≥65 years, or continuous 

for models stratified by age), sex, race/ethnicity, 

admission date (biweekly), and HHS region 
Group

Days since most 

recent dose, 

median (IQR)

Vaccinated 

COVID-19 

cases/total 

cases (%)

Vaccinated 

controls/ total 

controls (%)

Adjusted VE

% (95% CI)

2 doses

14–150 days 108 (72–128) 64/881 (7) 86/607 (14) 62 (45–74)

>150 days 301 (247–375) 545/1362 (40) 486/1007 (48) 33 (21–44)

3 doses

7–120 days 72 (47–109) 175/992 (18) 403/924 (44) 77 (71–82)

>120 days 185 (153–217) 428/1245 (34) 423/944 (45) 36 (20–49)

4 doses*

7–120 days 45 (26–66) 61/642 (10) 96/410 (23) 62 (42–75)

>120 days Not estimated Not estimated Not estimated Not estimated

0 10 20 30 40 50 60 70 80 90 100

Vaccine Effectiveness (%)

IVY Network: mRNA VE against hospitalization among immunocompetent

adults during Omicron period, Dec 26, 2021–Jul 31, 2022

* Only estimated among adults ≥50 years of age

2-dose VE

3-dose VE

4-dose VE
Days since 

most recent 

dose, 

median (IQR)

Vaccinated 

COVID-19 

cases/total 

cases (%)

Vaccinated 

controls/ total 

controls (%)

Adjusted VE

% (95% CI)

3 doses

7–120 days 75 (46–101) 112/298 (38) 174/299 (58) 66 (48–78)

>120 days 184 (150–224) 248/434 (57) 222/347 (64) 37 (12–55)

IVY Network: mRNA VE against hospitalization among immunocompromised

adults during Omicron period, Dec 26, 2021–Jul 31, 2022

* Not enough data to estimate 2 or 4-dose VE.

0 10 20 30 40 50 60 70 80 90 100

Vaccine Effectiveness (%)

3-dose VE
Summary
▪ Effectiveness against severe disease continues to be higher and more sustained over 

time than effectiveness against infection

▪ VE during BA.4/BA.5 predominance was generally comparable to VE during BA.2 

predominance 

▪ 3

rd dose provides significant additional protection against infection and severe 

disease in all ages studied

– VE post 3rd dose appears to wane more slowly compared with 2 doses alone 

during Omicron

– Similar patterns across age groups

▪ Coverage with 4th dose too low to draw conclusions but additional benefits 

demonstrated for infection, ED/UC, and hospitalization

Vaccine effectiveness during Omicron

19
CDC COVID-19 Vaccine 

Effectiveness and Policy Team

▪ Tamara Pilishvili

▪ Sara Oliver

▪ Amadea Britton

▪ Allison Ciesla

▪ Monica Godfrey

▪ Katherine Fleming-Dutra

▪ Morgan Najdowski

▪ Lauren Roper

▪ Evelyn Twentyman

▪ Ryan Wiegand

PIs and study staff for ICATT, VISION, 

COSMOS, IVY

▪ Katherine Adams

▪ Levi Bonnell

▪ Alexandra Dalton

▪ Ashley Fowlkes

▪ Matthew Levy

▪ Samantha Olson

▪ Manish Patel

▪ Zach Smith

▪ Diya Surie

▪ Mark Tenforde

Acknowledgements

20

▪ Mark Thompson

▪ Laura Zambrano

▪ Joe Deckert

▪ Eric Barkley

▪ Alex Piff

▪ Caleb Cox

▪ Johnston Thayer
For more information, contact CDC

1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.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.