Effectiveness of mRNA Vaccines Against COVID-19 Hospitalization by Age and Chronic Medical Conditions Burden Among Immunocompetent US Adults, March-August 2021
Nathaniel M. Lewis, Eric A. Naioti, Wesley H. Self, Adit A. Ginde, David J. Douin, H. Keipp Talbot, Jonathan D. Casey, Nicholas M. Mohr, Anne Zepeski, Manjusha Gaglani, Shekhar Ghamande, Tresa A McNeal, Nathan I. Shapiro, Kevin W. Gibbs, D. Clark Files, David N. Hager, Arber Shehu, Matthew E. Prekker, Heidi L. Erickson, Michelle N. Gong, Amira Mohamed, Daniel J. Henning, Jay S. Steingrub, Ithan D. Peltan, Samuel M. Brown, Emily T. Martin, Kinsley Hubel, Catherine L. Hough, Laurence W. Busse, Caitlin C. ten Lohuis, Abhijit Duggal, Jennifer G. Wilson, Alexandra June Gordon, Nida Qadir, Steven Y. Chang, Christopher Mallow, Carolina Rivas, Hilary M. Babcock, Jennie H. Kwon, Matthew C. Exline, Natasha Halasa, James D. Chappell, Adam S. Lauring, Carlos G. Grijalva, Todd W. Rice, Jillian P. Rhoads, William B. Stubblefield, Adrienne Baughman, Kelsey N. Womack, Christopher J. Lindsell, Kimberly W. Hart, Yuwei Zhu, Stephanie J. Schrag, Miwako Kobayashi, Jennifer R. Verani, Manish M. Patel, Mark W. Tenforde, IVY Network Collaborators, Tresa McNeal, Shekhar Ghamande, Nicole Calhoun, Kempapura Murthy, Judy Herrick, Amanda McKillop, Eric Hoffman, Martha Zayed, Michael Smith, Natalie Settele, Jason Ettlinger, Elisa L. Priest, Jennifer D. Thomas, Alejandro C. Arroliga, Madhava Beeram, Ryan Kindle, Lori-Ann Kozikowski, Lesley De Souza, Scott Ouellette, Sherell Thornton‐Thompson, Patrick D. Tyler, Omar Mehkri, Meg Mitchell, Connery Brennan, Kiran Ashok, Bryan Poynter, Nicholas Stanley, Audrey Hendrickson, Sean Caspers, Tyler Scharber, Jeffrey L. Jorgensen, Robert R. Bowers, Jennifer King, Valerie Aston, Brent Armbruster, Richard E. Rothman, R. Nair, Jen-Ting Chen, Sarah Karow, Emily Robart, Paulo Nunes Maldonado, Maryiam Khan
Abstract
Vaccine effectiveness (VE) against COVID-19 hospitalization was evaluated among immunocompetent adults (≥18 years) during March-August 2021 using a case-control design. Among 1669 hospitalized COVID-19 cases (11% fully vaccinated) and 1950 RT-PCR-negative controls (54% fully vaccinated), VE was 96% (95% confidence interval [CI], 93%-98%) among patients with no chronic medical conditions and 83% (95% CI, 76%-88%) among patients with ≥ 3 categories of conditions. VE was similar between those aged 18-64 years versus ≥65 years (P > .05). VE against severe COVID-19 was very high among adults without chronic conditions and lessened with increasing comorbidity burden.