Even as some governments and pharma companies plan for a booster shot of Covid vaccines to tackle the more infectious strains, the World Health Organisation has said that it's too early to say whether it's needed or not.
WHO chief scientist Soumya Swaminathan has said that the "science is still evolving" on the issue and that there is currently not enough information to recommend one way or the other, news agency Bloomberg has reported.
Swaminathan termed the calls for booster shots "premature" when even the most high-risk individuals in most countries haven't got their first shot.
Data from countries introducing precautionary extra inoculations later this year -- particularly for vulnerable people whose immunity to SARS-CoV-2 may wane faster -- will inform WHO's guidance, she said.
Covid booster shots are likely to be rolled out in U.K. in the fall to avoid another winter surge.