Facebook will ban anti-vaccination ads on its site.
It says it doesn't want the ads in a reversal of its long-held position of steering clear of sensitive issues.
The social media company already shuns ads about coronavirus vaccine hoaxes - like the falsehood treatments cause autism. Facebook's latest move includes a ban on ads that discourage vaccines for any reason.
Facebook's objective is to "help messages" with regard to the safety and effectiveness of vaccines reach a large group of people, while "prohibiting ads with misinformation that could harm public health efforts," The New York Times quoted Kang-Xing Jin, Facebook's director of health initiatives, as saying in a blog post.
Theories about COVID are being disseminated through social media - sparking anti-lockdown demonstrations.
But the company said ads that "advocate for or against government policies around vaccines" - including a vaccine for COVID - will still be allowed. Facebook said it will also initiate an information drive encouraging people to have flu shots this year. The campaign is set to start in the U.S. in the next few days and later in other nations.
In April, the company said it would employ new measures to regulate, including enabling users to know if they liked, reacted or commented on a post with damaging information about the virus.
Facebook earlier said it would take down posts that denied the existence of the Holocaust. Days before that, it expanded a clampdown on the pro-Trump conspiracy group QAnon and also disclosed it would halt all political advertising after the Nov. 3 U.S. presidential election.
Facebook has banned other individuals and organizations around the world and removed more than 22 million items of hate speech in the second quarter.