A UK study that tested seven different COVID-19 vaccines as booster doses found that most of them produced increased antibodies, with the shots from Moderna Inc. and the Pfizer Inc.-BioNtech SE partnership being the best. are performed.
The results, published Thursday, tested the vaccines in more than 2,800 volunteers aged 30 and older who had already received either AstraZeneca plc or two doses of Pfizer shots. The study found that all seven vaccines showed increased immunity after the Astra vaccine compared to placebo, while six after Pfizer showed increased antibody levels.
Nevertheless, there were large variations between antibody and cellular immune responses to the different vaccines, with messenger-RNA vaccines from Pfizer and Moderna showing the greatest increase. Antibody levels were measured four weeks after the booster was given.
It is not clear how many doses of vaccines will be needed to provide the longest-lasting protection, or whether annual COVID shots will be needed, but antibody levels induced by many vaccines tend to decrease after a few months, With the proliferation of the new Omicron variant, the booster to take the matter further, countries want to protect their populations as quickly as possible.
The Valneva SE vaccine, which performed well in trials but has not yet been authorized for use, was the only shot that did not increase antibody levels after two doses of Pfizer compared to placebo, although the vaccine was tested only Was done in about 100. People. The study found that all seven shots were safe to use as a third dose.
Other vaccines tested were from Johnson & Johnson, CureVac NV and Novavax Inc. The shots were given 10 to 12 weeks after the second dose of Astra or Pfizer vaccines.
Early results from the study were used in September to inform Britain’s initial booster programme, which focused on older people and relied on Pfizer and Moderna shots as the third dose. The UK expanded the rollout of the booster to all adults this week in light of the new Omicron version, reducing the time period of six months after the second dose to three.
“These data are directly relevant to the decision-making this week,” Saul Faust, professor of pediatrics immunology and infectious diseases and the study’s principal investigator, said in a press briefing. If “there’s only one vaccine in a country or region in the world that we’ve shown, it would be fine to use as a booster and it would be safe to do it. It’s not all about the mRNA.”
Most vaccines also produced good T-cell responses, which are another arm of a person’s immune defense, although Valneva’s effect as a booster was less strong.
Three vaccines are not yet authorized in the UK or the European Union. CureVac dropped its first-generation vaccine in October after disappointing test results. Novavax is expected to receive approval in Europe in the coming weeks, while Valneva should receive a green signal from the UK and EU early next year.
(Except for the title, this story has not been edited by NDTV staff and is published from a syndicated feed.)