A U.K. study testing seven different Covid-19 vaccines as booster doses found most of them increased antibodies, with shots from Moderna Inc. and the Pfizer Inc.-BioNTech SE partnership performing best.
The results, published Thursday, tested the vaccines in more than 2,800 volunteers 30 and older who had already received two doses of the AstraZeneca Plc or Pfizer shots. All seven vaccines boosted immunity after the Astra vaccine, compared with a placebo, while six raised antibody levels after Pfizer, the study found.