Facebook is to take a stand against vaccine denial by directing people searching for information or using vaccine hashtags to web pages set up by public health bodies.

People who access Facebook and Instagram pages and groups that discuss vaccines, as well as those searching or using relevant hashtags, will see an educational module about vaccine safety. Links will take them to a page provided by the Centers for Disease Control and Prevention (CDC) in the United States and to the World Health Organization elsewhere in the world.

There has been great concern in the public health community that anti-vaccine sentiment is spreading globally through social media – and in particular through Facebook groups. A report in January found that half of all UK parents of small children had been exposed to misinformation online about the side-effects of vaccination. The Royal Society for Public Health, which published the report, called on Facebook and other social media to do more.

In February, the Guardian found that Facebook users were inadvertently steered by popularity algorithms towards unscientific anti-vaccine propaganda.

Several social media platforms have already acted. YouTube undertook earlier this year to reduce the numbers of videos that could promulgate harmful misinformation. Pinterest last week said it would direct people seeking vaccine information to answers on web pages of major public health organisations.

Facebook’s move will have a bigger impact because of its greater reach around the world. WHO’s director-general, Tedros Adhanom Ghebreyesus, said he welcomed the commitment to direct millions of its users to WHO’s “accurate and reliable vaccine information in several languages, to ensure that vital health messages reach people who need them the most”.

It follows months of discussion between WHO and Facebook on ways to reduce the spread of misinformation.

“Vaccine misinformation is a major threat to global health that could reverse decades of progress made in tackling preventable diseases,” he said.

“Many debilitating and deadly diseases can be effectively prevented by vaccines. Think measles, diphtheria, hepatitis, polio, cholera, yellow fever, influenza.

“Major digital organisations have a responsibility to their users to ensure that they can access facts about vaccines and health. It would be great to see social and search platforms come together to leverage their combined reach. We want digital actors doing more to make it known around the world that vaccines work.

“We want innovation that supports healthy behaviours to save lives and protect the vulnerable. So many children whose parents fully support vaccination currently lack access to these life-saving tools.”

Tedros called on governments and the health sector to match the online push by taking “tangible steps” to promote trust in vaccinations and respond to the needs and concerns of parents.

Dr Heidi Larson, who runs the Vaccine Confidence Project at the London School of Hygiene and Tropical Medicine, said: “We welcome Facebook’s efforts to mitigate the spread of misinformation about vaccines and connect people to sources of accurate information … social media response is an important dimension of our broader efforts to build trust and confidence in immunisation.”