Scientists have said the Pfizer vaccine has lower antibody levels targeting the Indian variant, which are lower with increasing age.
Booster jabs will be needed for vulnerable people this autumn to protect against the Indian variant compared to other strains.
The data, from the Francis Crick Institute and the National Institute for Health Research (NIHR) UCLH Biomedical Research Centre support to reduce the gap between jabs.
Emma Wall, an infectious diseases consultant and a research fellow said, “This virus will likely be around for some time to come, so we need to remain agile and vigilant.
“Our study is designed to be responsive to shifts in the pandemic so that we can quickly provide evidence on changing risk and protection.
“The most important thing is to ensure that vaccine protection remains high enough to keep as many people out of hospital as possible.
“And our results suggest that the best way to do this is to quickly deliver second doses and provide boosters to those whose immunity may not be high enough against these new variants.”
Professor Eleanor Riley, of immunology and infectious disease, University of Edinburgh said, “These data cannot tell us whether the vaccine will be any less effective at preventing severe disease, hospitalisation and death; we need to wait for the actual data on these outcomes.”