AIDS is caused by a human immunodeficiency virus (HIV), which originated in non-human primates in Central and West Africa. While various sub-groups of the virus acquired human infectivity at different times, the present pandemic had its origins in the emergence of one specific strain – HIV-1 subgroup M – in Léopoldville in the Belgian Congo in the 1920s.

The GMHC is a New York City–based non-profit, volunteer-supported and community-based AIDS service organization whose mission statement is to "end the AIDS epidemic and uplift the lives of all affected." Founded in 1982, it is often billed as the "world's oldest AIDS service organization," as well as the "nation's oldest HIV/AIDS service organization."