INCIDENCE OF HIV-1 INFECTION AMONG YOUNG MEN IN THAILAND

Royal Thai Army (RTA) enlistees were tested for HIV-1 seropositivity p rospectively in order to explore their feasibility as a cohort in an H IV-1 preventive vaccine efficacy trial. The 17,615 seronegative enlist ees, virtually all 21-year-old men, contributed 10,409 person-years (p -y) of follow-up. Cohorts were enlisted in November 1991 acid May 1992 from northern Thailand and Bangkok. The follow-up rate was 50%, with loss to follow-up significantly associated with location of the base, marital status, and educational level. Seroincidence was 0.5/100 p-y f or recruits stationed in Bangkok, 1.0/100 p-y in the lower north, and 3.2/100 p-y in the upper north. In a multiple regression model, the yo ung man's birthplace was strongly associated with risk of infection, s uggesting that transmission occurred during leave as well as during du ty. Incidence rates were significantly lower in those who were married at the time of enlistment and in those with greater than or equal to 10 years of education. The seroincidence rates among recruits statione d in the upper north support vaccine trial feasibility, but follow-up rates need to be improved.