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Nearly one third of Britons definitely will not or are unsure about whether they would take a vaccine for coronavirus, according to a new poll.

Researchers say the results are in response to the dramatic rise in popularity of so-called “anti-vaxx” conspiracy theories widely spread on social media.

A poll of 1,663 people in the UK, conducted by YouGov for the Centre for Countering Digital Hate (CCDH), found 6% of respondents said they would definitely refuse a vaccine, and a further 10% said they would “probably not”. Another 15% said they were not sure.

The survey also found people who relied on social media above traditional media for information were less likely to take a vaccine.

The CCDH said the poll showed there is a credible “threat to the ability of a vaccine to contain Covid-19.”

In a separate report, the CCDH analysed more than 400 anti-vaxx accounts on Facebook, YouTube, Twitter and Instagram with more than 57 million followers in the US and UK. 

These social media accounts were found to be publishing false conspiracy theories including that Microsoft co-founder Bill Gates had created the coronavirus pandemic and that Covid-19 vaccine tests had caused women to be infertile.

The study concluded the number of followers of these accounts had increased by 7.7 million since the outbreak of coronavirus.

The CCDH said social media companies had “chosen to adopt lenient policies” on anti-vaxx content by promising only to reduce the ease which users can find such false information instead of removing them altogether.

Imran Ahmed, chief executive of CCDH, said: “Our hope for a return to normal life rests with scientists developing a successful vaccine for coronavirus.

“But social media companies’ irresponsible decision to continue to publish anti-vaccine propaganda means a vaccine may not be effective in containing the virus.

“The price for their greed is a cost paid in lives,” Ahmed said.

“There is simply no responsible justification for publishing lies and conspiracy theories about vaccines.”

Shadow culture secretary Jo Stevens said the poll showed the increasing popularity of anti-vaxx theories could “literally be a question of life and death”.

“This poll lays bare just how dangerous disinformation online can be,” she said.

“The rapid spread of false information about vaccinations could literally be a question of life and death.

“Social media companies must ensure this content has no place on their platforms and ministers must do more to promote the benefits of vaccines and counter the harmful, dangerous myths which surround them before a coronavirus vaccine becomes available.”

A representative from Facebook said: “We are working to stop harmful misinformation from spreading on our platforms and have removed hundreds of thousands of pieces of Covid-19-related misinformation.

“We reduce vaccine misinformation in News Feed, we don’t show it in search results or recommend it to you on Facebook or Instagram, we don’t allow it in ads, and we connect people with authoritative information from recognised health experts.” 

A government spokesperson said: “The science is clear – vaccines save lives, which is why we are leading a global effort to find a Covid-19 vaccine. 

“Vaccine misinformation in any form is completely unacceptable and it is everyone’s responsibility to seek NHS advice, so that they have the right information to make the right choice.”