A British member of Parliament blasted Facebook on Wednesday over its handling of anti-vaccine content and warned that the social media platform risks undermining Covid-19 vaccines just as vaccination programs are getting underway.

 “Today in the UK, the Pfizer vaccine has received regulatory approval and the first doses will be administered next week,” said MP Damian Collins, former Chair of the UK House of Commons Digital, Culture, Media and Sport Select Committee. “One of the greatest risks to the success of this program is anti-vaccine disinformation warning people not to take it.”

Collins’ remarks came during a public session of the International Grand Committee on Disinformation, a body that includes government officials from the United States, the UK, Canada, Germany, Ireland, India, Brazil and several other countries. The US was represented by Rep. David Cicilline, a leading tech critic and chairman of the House Judiciary Committee’s antitrust panel, and Rep. Jan Schakowsky, who chairs the House Energy and Commerce Committee’s consumer protection subcommittee.

Citing research reports on anti-vaccine content on Facebook, Collins said the platform’s “own algorithms are pushing anti-vax content over authentic health information. The impact of this is declining trust in the vaccine.”

“This is not just a public health challenge, but why legislation to combat harmful disinformation is so necessary,” he added. Next year, Collins, said, the UK parliament is expected to debate a bill that could establish a new regulator for online harms modeled after similar agencies that govern tech platforms’ handling of user data and privacy.

Facebook spokesman Andy Stone said the company removes misinformation about the coronavirus that could lead to “imminent physical harm” and directs users to Facebook’s Covid-19 information center, which is available in 189 countries. Stone added that Facebook has banned advertisements that discourage people from getting vaccines.

On Monday, during a livestream with Dr. Anthony Fauci, Facebook CEO Mark Zuckerberg said the company is “planning a push” to provide users with authoritative sources of vaccine information. Zuckerberg said that Facebook has already reached out to President-elect Joe Biden’s transition team about helping with the pandemic response.