In brief: Facebook's battle against anti-vaccination content is continuing. The social network is now rolling out a feature that will see pop-ups direct people searching for information on vaccines to web pages from authoritative health organizations.

The "educational" messages will appear for people who access vaccine-related Facebook and Instagram Pages and Groups. Searching for the topic or using related hashtags will also show the pop-up.

Those in the US will be directed to the Centers for Disease Control and Prevention's (CDC) website, which offers an extensive amount of information on vaccinations. People outside of America will see a link to the World Health Organization's site.

Back in March, Facebook said it would be reducing the ranking of Groups and Pages "that spread misinformation about vaccinations," which means they won't show up as much in the news feed and search results. Moreover, they won't be included in recommendations or predictions when typing in the search bar.

Facebook also stopped allowing ads that include misinformation about vaccines and removed targeted advertising options such as "vaccine controversies."

Facebook and Instagram aren't alone in their fight to tackle anti-vax content. YouTube earlier this year targeted channels promoting anti-vaccinations, alternative and holistic medicine, or other forms of pseudoscience by demonetizing them and preventing them from running ads.

Pinterest, meanwhile, is only surfacing results from official health groups when users search for immunizations, and Indiegogo has banned anti-vaccine projects, introducing a new policy that requires health claims to be backed by scientific evidence.

The spread of anti-vaccine content on social media has been partly blamed on the number of new measles cases in the US. The situation means the World Health Organization could soon revoke America's measles-elimination status---something it did for the UK last month.

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