New variants raise questions about vaccine efficacy, says WHO chief

The head of the World Health Organisation said the emergence of new Covid-19 variants has raised questions about whether or not existing vaccines will work.

The head of the World Health Organisation said the emergence of new Covid-19 variants has raised questions about whether or not existing vaccines will work.

Dr Tedros Adhanom Ghebreyesus called it "concerning news" that the vaccines developed so far may be less effective against the variant first detected in South Africa.