Effectiveness of a bivalent mRNA vaccine booster dose to prevent severe COVID-19 outcomes: a retrospective cohort study
Description
BACKGROUND: In late 2022, the SARS-CoV-2 omicron (B.1.1.529) BA.5 sublineage accounted for most of the sequenced viral genomes worldwide. Bivalent mRNA vaccines contain an ancestral SARS-CoV-2 strain component plus an updated component of the omicron
