HIV seroprevalence in five key populations in Europe: a systematic literature review, 2009 to 2019

Background: In Europe, HIV disproportionately affects men who have sex with men (MSM), people who inject drugs (PWID), prisoners, sex workers, and transgen-der people. Epidemiological data are primarily avail-able from national HIV case surveillance systems that rarely capture information on sex work, gender iden-tity or imprisonment. Surveillance of HIV prevalence in key populations often occurs as independent stud-ies with no established mechanism for collating such information at the European level. Aim: We assessed HIV prevalence in MSM, PWID, prisoners, sex workers, and transgender people in the 30 European Union/ European Economic Area countries and the United Kingdom. Methods: We conducted a systematic lit-erature review of peer-reviewed studies published during 2009-19, by searching PubMed, Embase and the Cochrane Library. Data are presented in for-est plots by country, as simple prevalence or pooled across multiple studies. Results: Eighty-seven coun- try-and population-specific studies were identified from 23 countries. The highest number of studies, and the largest variation in HIV prevalence, were identi-fied for MSM, ranging from 2.4-29.0% (19 countries) and PWID, from 0.0-59.5% (13 countries). Prevalence ranged from 0.0-15.6% in prisoners (nine countries), 1.1-8.5% in sex workers (five countries) and was 10.9% in transgender people (one country). Individuals belonging to several key population groups had higher prevalence. Conclusion: This review demonstrates that HIV preva-lence is highly diverse across population groups and countries. People belonging to multiple key popu-lation groups are particularly vulnerable; however, more studies are needed, particularly for sex workers, transgender people and people with multiple risks.