When Pinterest realized in 2018 that the search results for many health-related terms – such as “vaccines” or “cancer cure” – were polluted with non-scientific misinformation, the visual social media site took a radical step: it broke the search function for those terms. “If you’re looking for medical advice, please contact a healthcare provider,” a message on the otherwise blank page read.

On Wednesday, Pinterest announced a new step in its efforts to combat health misinformation on its platform: users will be able to search for 200 terms related to vaccines, but the results displayed will come from major public health organizations, including the World Health Organization (WHO), Centers for Disease Control, American Academy of Pediatrics (AAP) and Vaccine Safety Net.

The platform will also bar advertisements, recommendations and comments on those pages.

“It was really important for us to make sure that this experience doesn’t allow any misinformation to seep in,” said Ifeoma Ozoma, public policy and social impact manager for Pinterest. “You’re not going to end up in a situation where you click on a trustworthy pin and the recommendations or comments are full of misinformation.”

Social media platforms have faced significant criticism over their platforms’ promotion of anti-vaccine propaganda this year, as measles outbreaks spread in the US, Europe and Asia. A report by the Royal Society for Public Health found that half of all parents with small children in the UK had been exposed to misinformation about vaccines on social media.

“We know that the majority of parents turn to the internet to get all sorts of information about health,” said Dr David Hill, a pediatrician from Goldsboro, North Carolina, and the immediate past president of AAP’s council on communications and media. “A tremendous amount of really toxic vaccine misinformation spreads on the internet and social media.”

Most of the major platforms adopted new policies toward anti-vaccine misinformation this spring in response to pressure from public health organizations, politicians and the press. Facebook began reducing the reach of groups and pages that spread “verifiable vaccine hoaxes”, Amazon removed several anti-vaccine propaganda movies from its streaming video service, and YouTube moved to include anti-vaccine misinformation in a category of “harmful” misinformation videos that are not promoted by its recommendation algorithm.

YouTube also began including a box on some videos about vaccines that includes a snippet of information about, for example, the measles, mumps and rubella vaccine and a link to a Wikipedia article. Facebook has said it is also exploring ways to include accurate information at the top of certain search results or pages.

Previously, Pinterest would return a blank search for vaccine-related search terms. Photograph: Pinterest

But Pinterest’s policy moves have been the most aggressive. In addition to breaking and re-making the search tool, the company explicitly bans “anti-vaccination advice”. It has banned a number of prominent anti-vaccinegroups, and blocks users from pinning anything from certain anti-vaccine websites by blocking the entire URL. Hundreds of URLS have been blocked and hundreds of thousands of pins removed under the policy, Ozoma said.

The company is skeptical of the approaches of rival companies, which Ozoma said was in some ways making it harder for Pinterest to keep misinformation off its own site.

“We think there is a responsibility for us and other platforms to do more than just include a link to legitimate information,” said Ozoma. “There’s content coming from other sites that we’re not able to detect as easily … because it’s not actually being blocked or removed by other platforms. They’re adding labels or more legitimate information, but not actually removing it.”

Pinterest’s initiative earned praise from global health groups. Isabelle Sahinovic of the Vaccine Safety Network called it a “a critical addition to the global health community’s efforts to tackle incorrect and harmful misinformation online” in an emailed statement.

“Different initiatives have been piloted by other social media platforms but to date, Pinterest has taken the boldest step by asking for expert advice to improve their vaccine-related search results,” she added.

Hill of the AAP said: “As the entire industry asks itself how to come to terms with the vast influence social media has over people’s day-to-day decisions, I hope that more platforms will look to the steps that Pinterest has taken as a viable model for socially responsible communications.”

Dr Katherine O’Brien, the director of immunization, vaccines and biologicals for the WHO, also praised the effort to “create a healthier digital environment”, though she warned that the “current laser focus on the anti-vaccination phenomenon” could hamper efforts to increase vaccination uptake in countries lacking primary health systems.

“Social media platforms are the way many people get their information and they will likely be major sources of information for the next generations of parents,” O’Brien said. “We hope to see more engagement from digital platforms in the future to provide credible health information to their users, while taking real-time actions to halt the spread of harmful content when it occurs.”

Dr Tedros Adhanom Ghebreyesus, director-general of the WHO, added: “Misinformation about vaccines is as contagious and dangerous as the diseases it helps to spread. We’re delighted that Pinterest is leading the way in protecting public health by only providing evidence-based information about vaccines to its users. We hope to see many other social media platforms following Pinterest’s lead.”