Fig. 1. Vaccine effectiveness estimates with 95% confidence intervals of the ChAdOx1-S and BNT162b2 booster vaccines against hospitalisation as defined by linkage to the secondary care (SUS) data following infection with Delta (black squares) or Omicron (grey circles) variants in adults aged 65 years and older in England.

The ChAdOx1-S booster vaccine enhanced protection against hospitalisation following infection with both Delta and Omicron from seven days after the vaccine was received. Protection was lower than that observed following a BNT162b2 booster but still very high at 82.3% (64.2–91.3%) against the Omicron variant a week after receiving a ChAdOx1-S booster, as compared to the unvaccinated. Source data are provided as a Source Data file.