6 Vaccines Show Promise As Boosters, Led By Pfizer And Moderna
NDTV
All seven vaccines boosted immunity after the Astra vaccine, compared with a placebo, while six raised antibody levels after Pfizer, the study found.
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.
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.
It's unclear how many doses of the vaccines will be needed to provide the longest-lasting protection, or whether yearly Covid shots will be required, but the level of antibodies induced by a number of the vaccines wanes after a few months, pushing the case for boosters. With the new omicron variant spreading, countries are looking to protect their populations as quickly as they can.
