Protection Against the Omicron Variant Offered by Previous SARS-CoV-2 Infection: A Retrospective Cohort Study.
Michael B RothbergPriscilla KimNabin K ShresthaLisa KojimaLarisa G TereshchenkoPublished in: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America (2022)
Among the patients tested during the Omicron wave, 30.6% tested positive. Protection of prior infection against reinfection with Omicron ranged from 18.0% (95% confidence interval [CI], 13.0-22.7) for patients infected in wave 1 to 69.2% (95% CI, 63.4-74.1) for those infected in the Delta wave. In adjusted models, previous infection reduced hospitalization by 28.5% (95% CI, 19.1-36.7), while full vaccination plus a booster reduced it by 59.2% (95% CI, 54.8-63.1).