Nature Medicine
Volume 28 Issue 5, May 2022
https://www.nature.com/nm/volumes/28/issues/5

Article | 21 February 2022 | Open Access
Effectiveness of mRNA-1273 against SARS-CoV-2 Omicron and Delta variants
A test-negative case–control analysis using data from a diverse population in California, USA, demonstrates that vaccine efficacy of a three-dose regimen of the mRNA-1273 COVID-19 vaccine is reduced against infection with the Omicron SARS-CoV-2 variant in comparison to Delta, but that efficacy against hospitalization remained high for both variants.
Hung Fu Tseng, Bradley K. Ackerson, Lei Qian