<https://www.theguardian.com/technology/2019/feb/15/facebook-anti-vaccination...> Facebook enables advertisers to promote content to nearly 900,000 people interested in “vaccine controversies”, the Guardian has found. Other groups of people that advertisers can pay to reach on Facebook include those interested in “Dr Tenpenny on Vaccines”, which refers to anti-vaccine activist Sherri Tenpenny, and “informed consent”, which is language that anti-vaccine propagandists have adopted to fight vaccination laws. Facebook’s self-serve advertising platform allows users to pay to promote posts to finely tuned subsets of its 2.3 billion users, based on thousands of characteristics, including age, location, gender, occupation and interests. In some cases, users self-identify their interests, but in other cases, Facebook creates categories based on users’ online activity. In 2017, after a controversy involving antisemitic interest categories, Facebook vowed to build “new guardrails” on its targeting categories. Facebook is already facing pressure to stop promoting anti-vaccine propaganda to users amid global concern over vaccine hesitancy and a measles outbreak in the Pacific north-west. Facebook under pressure to halt rise of anti-vaccination groups On Thursday, California congressman Adam Schiff, the chair of the House intelligence committee, cited the Guardian’s reporting on anti-vaccine propaganda on Facebook and YouTube in letters to Mark Zuckerberg and Google CEO Sundar Pichai urging them to take more responsibility for health-related misinformation on their platforms. [...]