Positive results from a preliminary analysis of an ongoing safety and immunogenicity trial (D7220C00001) showed that Vaxzevria (ChAdOx1-S [Recombinant]), when given as a third dose booster, increased the immune response to Beta, Delta, Alpha and Gamma SARS-CoV-2 variants, while a separate analysis of samples from the trial showed increased antibody response to the Omicron variant.