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. 2022 May 17:ciac381. doi: 10.1093/cid/ciac381

Protection of mRNA vaccines against hospitalized COVID-19 in adults over the first year following authorization in the United States

Mark W Tenforde 1,*,, Wesley H Self 2,*,, Yuwei Zhu 2,*, Eric A Naioti 1, Manjusha Gaglani 3,4, Adit A Ginde 5, Kelly Jensen 5, H Keipp Talbot 2, Jonathan D Casey 2, Nicholas M Mohr 6, Anne Zepeski 6, Tresa McNeal 3,4, Shekhar Ghamande 3,4, Kevin W Gibbs 7, D Clark Files 7, David N Hager 8, Arber Shehu 8, Matthew E Prekker 9, Heidi L Erickson 9, Michelle N Gong 10, Amira Mohamed 10, Nicholas J Johnson 11, Vasisht Srinivasan 11, Jay S Steingrub 12, Ithan D Peltan 13, Samuel M Brown 13, Emily T Martin 14, Arnold S Monto 14, Akram Khan 15, Catherine L Hough 15, Laurence W Busse 16, Caitlin ten Lohuis 16, Abhijit Duggal 17, Jennifer G Wilson 18, Nida Qadir 19, Steven Y Chang 19, Christopher Mallow 20, Carolina Rivas 20, Hilary M Babcock 21, Jennie H Kwon 21, Matthew C Exline 22, Mena M Botros 22, Adam S Lauring 23, Nathan I Shapiro 24, Natasha Halasa 2, James D Chappell 2, Carlos G Grijalva 2, Todd W Rice 2, Ian D Jones 2, William B Stubblefield 2, Adrienne Baughman 2, Kelsey N Womack 2, Jillian P Rhoads 2, Christopher J Lindsell 2, Kimberly W Hart 2, Caitlin Turbyfill 1, Samantha Olson 1, Nancy Murray 1, Katherine Adams 1, Manish M Patel 1; For the Influenza and Other Viruses in the Acutely Ill (IVY) Network**
PMCID: PMC9129194  PMID: 35580849

Abstract

Background

COVID-19 mRNA vaccines were authorized in the United States in December 2020. Although vaccine effectiveness (VE) against mild infection declines markedly after several months, limited understanding exists on the long-term durability of protection against COVID-19-associated hospitalization.

Methods

Case control analysis of adults (≥18 years) hospitalized at 21 hospitals in 18 states March 11 – December 15, 2021, including COVID-19 case patients and RT-PCR-negative controls. We included adults who were unvaccinated or vaccinated with two doses of a mRNA vaccine before the date of illness onset. VE over time was assessed using logistic regression comparing odds of vaccination in cases versus controls, adjusting for confounders. Models included dichotomous time (<180 vs ≥180 days since dose two) and continuous time modeled using restricted cubic splines.

Results

10,078 patients were included, 4906 cases (23% vaccinated) and 5172 controls (62% vaccinated). Median age was 60 years (IQR 46–70), 56% were non-Hispanic White, and 81% had ≥1 medical condition. Among immunocompetent adults, VE <180 days was 90% (95%CI: 88–91) vs 82% (95%CI: 79–85) at ≥180 days (p < 0.001). VE declined for Pfizer-BioNTech (88% to 79%, p < 0.001) and Moderna (93% to 87%, p < 0.001) products, for younger adults (18-64 years) [91% to 87%, p = 0.005], and for adults ≥65 years of age (87% to 78%, p < 0.001). In models using restricted cubic splines, similar changes were observed.

Conclusion

In a period largely pre-dating Omicron variant circulation, effectiveness of two mRNA doses against COVID-19-associated hospitalization was largely sustained through 9 months.

Keywords: COVID-19, duration of protection, waning, vaccine effectiveness, mRNA

Supplementary Material

ciac381_Supplementary_Data

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ciac381_Supplementary_Data

Articles from Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America are provided here courtesy of Oxford University Press

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