U.K. Prime Minister Boris Johnson has branded opponents of vaccinations "nuts."
Speaking to staff at a medical facility in London Friday, Johnson said that "there's all these anti-vaxxers now, aren't there?" before adding, "they are nuts."
His comments come as pharmaceutical and biotech companies around the world embark on early stage testing for potential coronavirus vaccines.
Anti-vaccination activists, a vocal fringe who oppose inoculations, have organized protests in the wake of the current crisis. They believe, contrary to scientific evidence, that ingredients in a vaccine can cause harm to the body.
Unsubstantiated conspiracy theories about a pharmaceutical industry plot or Microsoft founder Bill Gates using the vaccine to implant tracking devices have also gained traction during the outbreak. Gates denied the debunked theory in an interview earlier this week.
In a YouGov survey in late June, one in six U.K. respondents said they "definitely" or "probably" would not get vaccinated for Covid-19 should a vaccine become available.
Johnson also told reporters that everyone in the U.K. should get a flu vaccine to prevent the country's National Health Service becoming overwhelmed should coronavirus cases flare up again in winter. Although he expressed concern over a possible second spike, the prime minister suggested that the country will be past the Covid-19 pandemic by mid-2021, according to Reuters.
—CNBC's Berkeley Lovelace Jr. contributed to this article.