Covid booster shots can dramatically strengthen the body’s immune defences, according to a study that raises hopes of preventing another wave of severe disease driven by the Omicron variant.
In a study published in the Lancet, researchers on the UK-based Cov-Boost trial measured immune responses in nearly 3,000 people who received one of seven Covid-19 boosters or a control jab two to three months after their second dose of either AstraZeneca or Pfizer vaccine.
Those boosted with Pfizer after two doses of AstraZeneca had antibody levels a month later nearly 25 times higher than controls. When the Pfizer booster was given following two Pfizer shots, antibody levels rose more than eightfold.
The most potent booster in the study was a full dose of the Moderna vaccine, which raised antibody levels 32-fold in the AstraZeneca group and 11-fold in the Pfizer group. When Moderna is used in the UK booster programme, it is given at a half-dose.