Any one of six different Covid-19 vaccines produce a strong immune system response and should work safely and well as boosters for people who have received initial vaccinations with either the Pfizer/BioNTech or AstraZeneca vaccines, British researchers reported Thursday.
They said their findings are especially important as studies show protection from two doses of these vaccines is waning. The new Omicron variant may evade some of the effects of vaccines, researchers reported in the Lancet medical journal..
And the longer the interval between the initial vaccine and the booster dose, the stronger the immune response, according to the research.
“It’s really encouraging that a wide range of vaccines, using different technologies, show benefits as a third dose to either AstraZeneca or Pfizer/BioNTech. That gives confidence and flexibility in developing booster programs here in the UK and globally, with other factors like supply chain and logistics also in play,” said Saul Faust of the University Hospital Southampton, who led the study team.
Study methods: The researchers randomly gave one of seven different boosters to more than 2,800 people, including vaccines made by AstraZeneca, Pfizer/BioNTech, Johnson & Johnson, Novavax, Moderna, Germany’s Curevac and France’s Valneva.
After four weeks, almost everyone had similar immune responses. AstraZeneca’s vaccine did not provide a strong boost if given to people initially vaccinated with the same vaccine, the researchers found. Otherwise, any of the vaccines boosted either vaccine well. The team will follow volunteers for at least a year.
What about Omicron? Faust said he hoped the boosters would work well against the Omicron variant, but noted that had not been tested. The researchers did not test people against real-life infection, but rather tested their blood for antibody responses — which studies have shown are good indicators of protection against infection.
Faust said the findings come at an important time. “With a new variant, we do need to try and get boosters into people,” he told reporters. “We’re right at the beginning of a very, very busy winter period.
“This is about just making sure we’ve got people as protected as possible.”