title: Role of primary infection in epidemics of HIV in gay cohorts.
authors.forename: D J
authors.initials: DJ
authors.lastname: Ahlgren
mesh_terms: D002641:Chicago / Q000453:epidemiology; D015331:Cohort Studies; D004196:Disease Outbreaks; D015658:HIV Infections / Q000453:epidemiology*; D018451:Homosexuality, Male; D006801:Humans; D008297:Male; D012495:San Francisco / Q000453:epidemiology