A U.K. study testing seven different COVID-19 vaccines as booster doses found most of them increased antibodies, with shots from Moderna and the Pfizer-BioNTech 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 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.
Still, there were large variations between the antibody and cellular immune responses of the different vaccines, with the biggest boosts seen from the messenger-RNA vaccines from Pfizer and Moderna. Antibody levels were measured four weeks after the booster was given.