Interim Estimates of Vaccine Effectiveness of Pfizer-BioNTech and Moderna COVID-19 Vaccines Among Health Care Personnel — 33 U.S. Sites, January–March 2021
Tamara Pilishvili, Katherine E. Fleming-Dutra, Jennifer L. Farrar, Ryan Gierke, Nicholas M. Mohr, David A. Talan, Anusha Krishnadasan, Karisa K. Harland, Howard Smithline, Peter C. Hou, Lilly C. Lee, Stephen C. Lim, Gregory J. Moran, Elizabeth Krebs, Mark T. Steele, David G. Beiser, Brett Faine, John P. Haran, Utsav Nandi, Walter A. Schrading, Brian Chinnock, Daniel J. Henning, Frank LoVecchio, Joelle Nadle, Devra Barter, Monica Brackney, Amber Britton, Kaytlynn Marceaux-Galli, Sarah Lim, Erin C. Phipps, Ghinwa Dumyati, Rebecca Pierce, Tiffanie Markus, Deverick J. Anderson, Amanda K. Debes, Michael Lin, Jeanmarie Mayer, Hilary M. Babcock, Nasia Safdar, Marc Fischer, Rosalyn Singleton, Nora Chea, Shelley S. Magill, Jennifer R. Verani, Stephanie J. Schrag, Vaccine Effectiveness Among Healthcare Personnel Study Team, Vaccine Effectiveness Among Healthcare Personnel Study Team, Anna R Yousaf, Yunmi Chung, Jennifer Onukwube, Wei Xing, Bradley Clinansmith, Lisandra Uribe, Kye E. Poronsky, Dean M. Hashimoto, Mónica Bahamón, Michelle St. Romain, Efrat Kean, Amy Stubbs, Sara Roy, Gregory Volturo, James Galbraith, James Crosby, Megan Fuentes, Mary Mulrow, Jane E. Lee, Helen Johnston, AmberJean P. Hansen, Scott K. Fridkin, Lucy Wilson, Sara Lovett, Melissa Christian, Christopher R. Myers, Valerie Ocampo, Keipp Talbot, Jessica Seidelman, Aaron M. Milstone, Mary K. Hayden, Matthew Samore, Jennie H. Kwon, Daniel Shirley, Denise A. Dillard, Jennifer Dobson
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.