Twitter is following in the footsteps of Facebook and Instagram by launching new tools to help prevent the spread of anti-vaccination misinformation.
Users will now be directed to a 'credible public health resource' when they conduct a search using specific keywords associated with vaccines, Twitter said on Tuesday.
The new tool is being rolled out on Twitter's iOS and Android apps, as well as its desktop website, for users in the US, Canada, UK, Brazil, Korea, Japan, Indonesia, Singapore and Spanish-speaking Latin American countries.
Twitter said the tool is being rolled out as part of its broader efforts to 'protect the health of public conversation' on its platform.
'At Twitter, we understand the importance of vaccines in preventing illness and disease and recognize the role that Twitter plays in disseminating important public health information,' Del Harvey, vice president of Trust and Safety at Twitter, said in a statement.
'We think it's important to help people find reliable information that enhances their health and well-being.'
For mobile users, a notice will appear in search results that says 'Know the facts' and directs users to 'vaccines.gov,' a resource managed by the U.S. Department of Health and Human Services.
On desktops, a tweet will be pinned to the top of search results from HHS.gov, directing users to the vaccines.gov website.
While the tool succeeds in preventing anti-vaxx content from being prominently featured in search results, it's not as effective in other areas.
Twitter's 'Who to Follow' column, which uses an algorithm to make account suggestions, still recommends that users follow accounts publishing anti-vaccination misinformation.
On Twitter's iOS app, an account with a bio that read 'Mother of vaccine injured child. Vaccines can and do cause autism,' appeared directly below the @HHSGov notice.
Two of the three suggested accounts in the column posted false information about vaccines being linked to autism.
When another search was conducted for 'vaccine dangers,' one of the three accounts recommended was run by a vaccine misinformation website.
Twitter's 'Who to Follow' tab makes recommendations using an algorithm that looks at a variety of factors when suggesting accounts.
It factors in which accounts you've viewed or interacted with, who you follow and your location, among other things.
Additionally, the notice that points users to credible vaccine information only appears in the 'Top' tab in Twitter's search results.
If users click on the 'Latest' or 'People' tabs, it will still show anti-vaccination misinformation.
Twitter has deployed similar search tools for other public health issues.
Harvey said the tool builds on a feature Twitter has deployed for searches about suicide or self-harm.
Last September, Twitter began showing a notice encouraging people to reach out for help when they search for terms associated with suicide or self-harm, as part of a partnership with the International Association for Suicide Prevention.
Harvey said on Tuesday that Twitter hopes to expand the feature to other 'important public health issues in the coming months'.
'This new investment builds on our existing work to guard against the artificial amplification of non-credible content about the safety and effectiveness of vaccines,' she added.
The move comes as tech giants have been facing increasing pressure to take steps to remove content promoting anti-vaccination misinformation.
Last week, Instagram said it would begin blocking hashtags that promote misinformation about vaccines
As part of the decision, vaccine misinformation will not be shown in Instagram's Explore, hashtag and search pages.
Facebook in March announced that it would demote the ranking of groups or pages that spread false information about vaccines in its News Feed and in search results.
Additionally, YouTube said in February that it would de-monetize videos with anti-vaccine content, while Pinterest said it would block all 'vaccine' searches altogether.