Misinformation and sceptical views about Covid-19 and vaccines has been allowed to spread on more than a dozen Facebook and Instagram accounts, pages and groups that together have gained 370,000 followers over the past year, according to a report.

The misinformation and promotion of vaccine hesitancy includes posts in Facebook groups claiming that children are being “murdered by the experimental jab they’re being pressured to take”, and an Instagram account promoting a documentary by Andrew Wakefield, one of the key figures in promoting discredited links between MMR inoculation and autism.

The 20 accounts, pages and groups have been tracked by NewsGuard, an organisation that monitors online misinformation. Since September last year NewsGuard has submitted regular reports to the World Health Organization, at the WHO’s request, flagging social media sites and other digital platforms that are spreading falsehoods about Covid-19.

In research published on Tuesday, NewsGuard said 20 of the sites that it had monitored over that period had gained a total of 372,670 followers. A full report containing the research has been sent to the WHO.

The NewsGuard research points to prominent sources of vaccine scepticism such as the Facebook pages of Robert F Kennedy Jr, a prominent anti-vaxxer, and Joseph Mercola, an alternative medicine doctor, as well as smaller sources such as the France Soir account on Instagram.

Kennedy was banned from Instagram over his vaccine stance in February but his Facebook page and Mercola’s Instagram account have gained more than 140,000 followers since February, according to NewsGuard. Mercola has said he has “every right to inform the public by sharing my medical research”.

Facebook came under pressure to ban Kennedy, the nephew of President John F Kennedy, in March when he released a documentary, Medical Racism, which has been accused of seeking to promote vaccine hesitancy among black Americans. Kennedy has said the film “empowers all Americans to demand the safest vaccines”.

Facebook and Instagram are both owned by Meta, the company that until a rebranding last week was known as Facebook.

Alex Cardier, the UK managing director for NewsGuard, said Facebook and Instagram were failing to protect their users from Covid-19 and vaccine misinformation despite having been warned “repeatedly”.

He said: “The company’s engagement-at-all-costs mantra means that viral and divisive sources of misinformation continue to flourish, despite warnings from NewsGuard and the clear danger posed to users. Facebook gave itself a new name but their promotion of misinformation remains the same.”

A Meta spokesperson said the company was encouraging users of its platforms to get vaccinated and it was taking action against misinformation. “During the pandemic we have removed more than 20m pieces of harmful misinformation and we’ve taken down content identified in this report which violates our rules. In total we’ve now banned more than 3,000 accounts, pages and groups for repeatedly breaking our rules. We’re also labelling all posts about the vaccines with accurate information and worked with independent factcheckers to mark 190m posts as false.”

In an effort to reassure users on the efficacy of vaccines, several of the Facebook pages highlighted by NewsGuard contained Facebook labels directing users to a WHO page on vaccines or the company’s own Covid-19 information centre page.

Meta announced last week that was stepping up efforts to promote vaccination efforts for children on its apps.