Bill Gates today warned anti-vaxxers could wreck attempts to develop a Covid-19 vaccine if they refuse to take it and reduce the level of herd immunity.
Over 80 per cent of people may need to have the jab for it to work properly – but he feared anti-vaccine ‘craziness’ might put people off getting it.
The billionaire founder of Microsoft, who now donates hundreds of millions of dollars to global health causes, said the prospect was ‘worrying’.
Vaccines can only be successful at stamping out a virus if so many people get them that a vast majority of the population is immune and the disease can no longer spread.
Mr Gates’s comments come as vaccine trials on humans are in full swing in the UK and the University of Oxford has announced it will test its candidate in Brazil now.
Falling levels of the virus circulating in Britain, where the outbreak is fading, means it will be increasingly difficult to test the vaccine because there is nothing to test it against.
In Brazil, however, Covid-19 cases are still rising rapidly and its outbreak is second only to the US, with 555,000 confirmed diagnoses.