Social media mining could be a possible strategy to retrieve drug safety information. The mining of social media is a complex process under progressive evolution, falling into three broad categories: listening (safety data reporting), engaging (follow-up), and broadcasting (risk communication). This systematic review is aimed at evaluating the usefulness and quality of proto-signals by social media listening. Areas covered: In this systematic search, performed according to MOOSE and PRISMA statements, we selected studies, published in MEDLINE, EMBASE, and Google Scholar until 31 December 2017, that listened at least one social media to identify proto-adverse drug events and proto-signals. Expert opinion: The selected 38 studies identified serious and unexpected proto-adverse drug events characterized by poorer information quality as compared with spontaneous reporting databases. This feature allows rarely the evaluation of causal relationships. Proto-signals identified by social media listening had the potential of anticipating pre-specified known signals in only six studies. Moreover, the personal perception of patients reported in social media could be used to implement effective risk communication strategies. However, signal detection in social media cannot be currently recommended for routine pharmacovigilance, due to logistic and technical issues.
Keywords: Social media; pharmacovigilance; proto-signal; signal detection.