Facebook Inc will start banning ads that explicitly discourage people from getting vaccinated, the world's largest social media company said on Tuesday, as it also announced a new flu vaccine information campaign.

Ads advocating for or against legislation or government policies around vaccines, including a COVID-19 vaccine, will still be allowed, the company said in a blog post.

It will begin to enforce the new global policy in the next few days.

Facebook, with 2.7 billion monthly active users, has been under pressure from lawmakers and public health groups to crack down on anti-vaccine content and misinformation on its platform.

The company said that although a COVID-19 vaccine would not be available for some time, the pandemic had highlighted the importance of preventative health behaviors.

Facebook’s previous rules prohibited ads containing vaccine misinformation or hoaxes identified by leading health organizations, but allowed ads opposing vaccines if they did not contain false claims.

This summer, Facebook Public Policy Manager Jason Hirsch told Reuters the company believed users should be able to express personal anti-vaccine views and that more aggressive censorship could push people hesitant about vaccines towards the anti-vaccine camp.

Facebook will also start directing U.S. users this week to information about the flu vaccine and how to get it, according to the company’s Head of Health Kang-Xing Jin and Director of Product Management Rob Leathern in the blog post.

Facebook is working with public health partners like the World Health Organization and UNICEF on messaging campaigns to increase immunization rates, they added.

Anti-vaccine content and misinformation about the new COVID-19 vaccines have flourished on social media platforms including Facebook during the coronavirus pandemic, researchers told Reuters earlier this year.

In September, the company also said it would stop recommending health-related Facebook groups, saying it was crucial that people get health information from “authoritative sources.”