Effectiveness of Pfizer-BioNTech and Moderna Vaccines in Preventing SARS-CoV-2 Infection Among Nursing Home Residents Before and During Widespread Circulation of the SARS-CoV-2 B.1.617.2 (Delta) Variant — National Healthcare Safety Network, March 1–August

"Weekly data reported by the Centers for Medicaid & Medicare (CMS)–certified skilled nursing facilities or nursing homes to CDC’s National Healthcare Safety Network (NHSN) were analyzed to evaluate effectiveness of full vaccination (2 doses received ≥14 days earlier) with any of the two currently authorized mRNA COVID-19 vaccines during the period soon after vaccine introduction and before the Delta variant was circulating (pre-Delta [March 1–May 9, 2021]), and when the Delta variant predominated (Delta [June 21–August 1, 2021]). Using 17,407 weekly reports from 3,862 facilities from the pre-Delta period, adjusted effectiveness against infection for any mRNA vaccine was 74.7% (95% confidence interval [CI] = 70.0%–78.8%). Analysis using 33,160 weekly reports from 11,581 facilities during an intermediate period (May 10–June 20) found that the adjusted effectiveness was 67.5% (95% CI = 60.1%–73.5%). Analysis using 85,593 weekly reports from 14,917 facilities during the Delta period found that the adjusted effectiveness was 53.1% (95% CI = 49.1%–56.7%). Effectiveness estimates were similar for Pfizer-BioNTech and Moderna vaccines. These findings indicate that mRNA vaccines provide protection against SARS-CoV-2 infection among nursing home residents; however, VE was lower after the Delta variant became the predominant circulating strain in the United States." - Effectiveness of Pfizer-BioNTech and Moderna Vaccines in Preventing SARS-CoV-2 Infection Among Nursing Home Residents Before and During Widespread Circulation of the SARS-CoV-2 B.1.617.2 (Delta) Variant — National Healthcare Safety Network, March 1–August

Additional Authors: Hsiu Wu, Qunna Li, Suparna Bagchi, Heather Dubendris, Ruth Link-Gelles, John A. Jernigan, Daniel Budnitz, Jeneita Bell, Andrea Benin, Nong Shang, Jonathan R. Edwards, Jennifer R. Verani, Stephanie J. Schrag