Estimated COVID-19 vaccine effectiveness against seroconversion from SARS-CoV-2 Infection, March-October, 2021

Ian D. Plumb, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA. Electronic address: iplumb@cdc.gov.
Lida M. Fette, Biostatistics Center, Milken Institute School of Public Health, The George Washington University, 6110 Executive Blvd., Suite 750, Rockville, MD 20852, USA.
Ashley H. Tjaden, Biostatistics Center, Milken Institute School of Public Health, The George Washington University, 6110 Executive Blvd., Suite 750, Rockville, MD 20852, USA.
Leora Feldstein, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA.
Sharon Saydah, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA.
Amina Ahmed, Atrium Health Levine Children's Hospital, 1000 Blythe Blvd, Charlotte, NC 28203, USA.
Ruth Link-Gelles, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA.
Thomas F. Wierzba, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
Andrea A. Berry, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W. Baltimore Street, Room 480, Baltimore, MD 21201, USA.
DeAnna Friedman-Klabanoff, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W. Baltimore Street, Room 480, Baltimore, MD 21201, USA.
Moira P. Larsen, Medstar Health Research Institute, 6525 Belcrest Road, Suite 700, Hyattsville, MD 20782, USA.
Michael S. Runyon, Department of Emergency Medicine, Atrium Health Carolinas Medical Center, 1000 Blythe Blvd, Charlotte, NC 28203, USA.
Lori M. Ward, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216, USA.
Roberto P. Santos, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216, USA.
Johnathan Ward, Vysnova Partners, 8400 Corporate Drive Suite 130, Landover, MD 20785, USA.
William S. Weintraub, Medstar Health Research Institute, 6525 Belcrest Road, Suite 700, Hyattsville, MD 20782, USA.
Sharon Edelstein, Biostatistics Center, Milken Institute School of Public Health, The George Washington University, 6110 Executive Blvd., Suite 750, Rockville, MD 20852, USA.
Diane Uschner, Biostatistics Center, Milken Institute School of Public Health, The George Washington University, 6110 Executive Blvd., Suite 750, Rockville, MD 20852, USA.

Document Type

Journal Article

Publication Date

4-6-2023

Journal

Vaccine

Volume

41

Issue

15

DOI

10.1016/j.vaccine.2023.03.006

Keywords

Adults; COVID-19; COVID-19 vaccines; SARS-CoV-2; Serology; Vaccine effectiveness

Abstract

BACKGROUND: Monitoring the effectiveness of COVID-19 vaccines against SARS-CoV-2 infections remains important to inform public health responses. Estimation of vaccine effectiveness (VE) against serological evidence of SARS-CoV-2 infection might provide an alternative measure of the benefit of vaccination against infection. METHODS: We estimated mRNA COVID-19 vaccine effectiveness (VE) against development of SARS-CoV-2 anti-nucleocapsid antibodies in March-October 2021, during which the Delta variant became predominant. Participants were enrolled from four participating healthcare systems in the United States, and completed electronic surveys that included vaccination history. Dried blood spot specimens collected on a monthly basis were analyzed for anti-spike antibodies, and, if positive, anti-nucleocapsid antibodies. We used detection of new anti-nucleocapsid antibodies to indicate SARS-CoV-2 infection, and estimated VE by comparing 154 case-participants with new detection of anti-nucleocapsid antibodies to 1,540 seronegative control-participants matched by calendar period. Using conditional logistic regression, we estimated VE ≥ 14 days after the 2nd dose of an mRNA vaccine compared with no receipt of a COVID-19 vaccine dose, adjusting for age group, healthcare worker occupation, urban/suburban/rural residence, healthcare system region, and reported contact with a person testing positive for SARS-CoV-2. RESULTS: Among individuals who completed a primary series, estimated VE against seroconversion from SARS-CoV-2 infection was 88.8% (95% confidence interval [CI], 79.6%-93.9%) after any mRNA vaccine, 87.8% (95% CI, 75.9%-93.8%) after BioNTech vaccine and 91.7% (95% CI, 75.7%-97.2%) after Moderna vaccine. VE was estimated to be lower ≥ 3 months after dose 2 compared with < 3 months after dose 2, and among participants who were older or had underlying health conditions, although confidence intervals overlapped between subgroups. CONCLUSIONS: VE estimates generated using infection-induced antibodies were consistent with published estimates from clinical trials and observational studies that used virologic tests to confirm infection during the same period. Our findings support recommendations for eligible adults to remain up to date with COVID-19 vaccination.

Department

Biostatistics and Bioinformatics

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