Interim Estimates of Vaccine Effectiveness of Pfizer-BioNTech and Moderna COVID-19 Vaccines Among Health Care Personnel - 33 U.S. Sites, January-March 2021

MMWR Morb Mortal Wkly Rep. 2021 May 21;70(20):753-758. doi: 10.15585/mmwr.mm7020e2.

Abstract

Throughout the COVID-19 pandemic, health care personnel (HCP) have been at high risk for exposure to SARS-CoV-2, the virus that causes COVID-19, through patient interactions and community exposure (1). The Advisory Committee on Immunization Practices recommended prioritization of HCP for COVID-19 vaccination to maintain provision of critical services and reduce spread of infection in health care settings (2). Early distribution of two mRNA COVID-19 vaccines (Pfizer-BioNTech and Moderna) to HCP allowed assessment of the effectiveness of these vaccines in a real-world setting. A test-negative case-control study is underway to evaluate mRNA COVID-19 vaccine effectiveness (VE) against symptomatic illness among HCP at 33 U.S. sites across 25 U.S. states. Interim analyses indicated that the VE of a single dose (measured 14 days after the first dose through 6 days after the second dose) was 82% (95% confidence interval [CI] = 74%-87%), adjusted for age, race/ethnicity, and underlying medical conditions. The adjusted VE of 2 doses (measured ≥7 days after the second dose) was 94% (95% CI = 87%-97%). VE of partial (1-dose) and complete (2-dose) vaccination in this population is comparable to that reported from clinical trials and recent observational studies, supporting the effectiveness of mRNA COVID-19 vaccines against symptomatic disease in adults, with strong 2-dose protection.

MeSH terms

  • Adult
  • Aged
  • COVID-19 / epidemiology
  • COVID-19 / prevention & control*
  • COVID-19 Testing
  • COVID-19 Vaccines / administration & dosage
  • COVID-19 Vaccines / immunology*
  • Case-Control Studies
  • Female
  • Health Personnel / statistics & numerical data*
  • Humans
  • Immunization Schedule
  • Male
  • Middle Aged
  • Occupational Diseases / epidemiology
  • Occupational Diseases / prevention & control*
  • United States / epidemiology
  • Young Adult

Substances

  • COVID-19 Vaccines