In recent years, social media have become an important marketplace. But it's not just everyday gadgets that are advertised on Facebook, Instagram, TikTok and the like. Medical researchers are also increasingly relying on social media advertising to recruit participants for clinical trials. After all, subway advertising for clinical trials has long since lost its appeal, because everyone is looking at their smartphones anyway - and subway passengers are also simply harder to target. Against this background, it seems logical to recruit especially hard-to-reach populations and people with rare diseases via social networks.

But should we really be doing this? The fundamental properties of social networks, especially the built-in predictive analytics, can have a number of negative effects when targeting such specific and vulnerable groups as people with certain diseases.

In this new article, RainerMühlhoff and Theresa Willem provide an overview of the ethical and privacy implications of online targeting for clinical trials.

They show how, in many cases, social media advertising for clinical trials (1) violates the privacy of individual users, (2) creates collective privacy risks by helping platform companies train predictive models of medical information that can be applied to all their users, (3) exploits the weaknesses of existing guidelines in (biomedical) research ethics, and (4) is detrimental to the quality of (biomedical) research. The well-intentioned promises of social media advertising for clinical trials are therefore untenable from a thoughtful perspective. The authors call for an update of research ethics guidelines and better regulation of Big Data and inferential analytics.

DOI: https://journals.sagepub.com/doi/epdf/10.1177/20539517231156127