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coronavirus disease 2019
CORONAVIRUS, CORONAVIRUS DISEASE 2019, SEVERE ACUTE RESPIRATORY SYNDROME
Booster immunization against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) improves immune responses and vaccine effectiveness against coronavirus disease 2019 (COVID-19) (refs. Due to the rapid SARS-CoV-2 evolution and the subsequent emergence of Omicron BA.4/BA.5 variants in spring and summer of 2022, a bivalent booster vaccine update containing the BA.4/BA.5 spike sequence (mRNA-1273.222) was also deployed to more closely match the dominant-circulating variant at the time. Given that the Omicron BA.4/BA.5 vaccine update had already been recommended as the standard-of-careHerein, we summarize the interim safety and immunogenicity results of the mRNA-1273.222 clinical study and we include neutralization information against variants that emerged after the Omicron BA.4/BA.5 wave. Rapid evaluation of variant-containing COVID-19 vaccines is important as vaccine updates are likely to be further recommended to enhance protection against COVID-19.