Absolute and Relative Vaccine Effectiveness of Primary and Booster Series of COVID-19 Vaccines (mRNA and Adenovirus Vector) Against COVID-19 Hospitalizations in the United States, December 2021-April 2022.

Abstract

Background:

Coronavirus disease 2019 (COVID-19) vaccine effectiveness (VE) studies are increasingly reporting relative VE (rVE) comparing a primary series plus booster doses with a primary series only. Interpretation of rVE differs from traditional studies measuring absolute VE (aVE) of a vaccine regimen against an unvaccinated referent group. We estimated aVE and rVE against COVID-19 hospitalization in primary-series plus first-booster recipients of COVID-19 vaccines.

Methods:

Booster-eligible immunocompetent adults hospitalized at 21 medical centers in the United States during December 25, 2021-April 4, 2022 were included. In a test-negative design, logistic regression with case status as the outcome and completion of primary vaccine series or primary series plus 1 booster dose as the predictors, adjusted for potential confounders, were used to estimate aVE and rVE.

Results:

A total of 2060 patients were analyzed, including 1104 COVID-19 cases and 956 controls. Relative VE against COVID-19 hospitalization in boosted mRNA vaccine recipients versus primary series only was 66% (95% confidence interval [CI], 55%-74%); aVE was 81% (95% CI, 75%-86%) for boosted versus 46% (95% CI, 30%-58%) for primary. For boosted Janssen vaccine recipients versus primary series, rVE was 49% (95% CI, -9% to 76%); aVE was 62% (95% CI, 33%-79%) for boosted versus 36% (95% CI, -4% to 60%) for primary.

Conclusions:

Vaccine booster doses increased protection against COVID-19 hospitalization compared with a primary series. Comparing rVE measures across studies can lead to flawed interpretations of the added value of a new vaccination regimen, whereas difference in aVE, when available, may be a more useful metric.

• Authors: Nathaniel M Lewis, Nancy Murray, Katherine Adams, Diya Surie, Manjusha Gaglani, Adit A Ginde, Tresa McNeal, Shekhar Ghamande, David J Douin, H Keipp Talbot, Jonathan D Casey, Nicholas M Mohr, Anne Zepeski, Nathan I Shapiro, Kevin W Gibbs, D Clark Files, David N Hager, Harith Ali, Matthew E Prekker, Anne E Frosch, Matthew C Exline, Michelle N Gong, Amira Mohamed, Nicholas J Johnson, Vasisht Srinivasan, Jay S Steingrub, Ithan D Peltan, Samuel M Brown, Emily T Martin, Arnold S Monto, Adam S Lauring, Akram Khan, Catherine L Hough, Laurence W Busse, William Bender, Abhijit Duggal, Jennifer G Wilson, Alexandra June Gordon, Nida Qadir, Steven Y Chang, Christopher Mallow, Carolina Rivas, Hilary M Babcock, Jennie H Kwon, James D Chappell, Natasha Halasa, Carlos G Grijalva, Todd W Rice, William B Stubblefield, Adrienne Baughman, Christopher J Lindsell, Kimberly W Hart, Jillian P Rhoads, Meredith L McMorrow, Mark W Tenforde, Wesley H Self, Manish M Patel, Influenza and Other Viruses in the Acutely Ill (IVY) Network
• Journal: Open forum infectious diseases (Open Forum Infect Dis) Vol. 10 Issue 1 Pg. ofac698 (Jan 2023) ISSN: 2328-8957 [Print] United States
• PMID: 36695662 (Publication Type: Journal Article)
• Copyright: © The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.