title: MACS passes 15-year mark and is still going strong.
mesh_terms: D001727:Bisexuality; D015331:Cohort Studies; D015658:HIV Infections / Q000517:prevention & control / Q000635:transmission*; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D015337:Multicenter Studies as Topic; D012107:Research Design; D012307:Risk Factors; D015229:Sexually Transmitted Diseases, Viral / Q000517:prevention & control / Q000635:transmission*; D014481:United States