Facebook says it will ban paid adverts on its platform that discourage people from getting vaccinated.
The latest policy is an extension of Facebook's rules that ban adverts about vaccine "hoaxes".
The social network said it will also run an information campaign encouraging people to get their flu shots in 2020.
But ads that "advocate for or against legislation or government policies around vaccines” — including a COVID-19 vaccine — will still be allowed on the platform.
These adverts still need to be approved by the company as political advertisements and will include a “paid for by” label flagging who funded them.
Any non-sponsored posts by people or groups that discourage vaccinations will not be removed from Facebook under the new rules.
While the social network has not extended its policy to anti-vax posts, Facebook announced in 2019 that it would begin hiding groups and pages that spread misinformation about vaccinations from the search function on its site.
Some analysts have said they are sceptical of the move by Facebook and suggested the new policy will only have an effect on half of the anti-vaccine content that exists on the platform.
The announcement is the latest in a series of moves by Facebook to address content ahead of the US Presidential election and comes just one day after CEO Mark Zuckerberg said content that denies the Holocaust would be banned from the platform.