HIV-1 INFECTION INCIDENCE AMONG PERSONS WITH HEMOPHILIA IN THE UNITED-STATES AND WESTERN-EUROPE, 1978-1990

We studied human immunodeficiency virus type 1 (HIV-1) infection incid ence over time in a 16-center cohort of hemophiliacs in the United Sta tes and Europe and estimated the most likely date of seroconversion fo r all sero-positive subjects. Five U.S. centers enrolled subjects inde pendent of HIV-1 status, whereas 11 centers preferentially included se ropositive subjects. We obtained unbiased estimates of HIV-1 infection incidence rates from the five centers and estimated dates of seroconv ersion from the distribution seen among seropositives from all centers . In the five-center cohort, infection incidence began in 1978, peaked in October 1982 at 22 infections per 100 person-years at risk, and de clined to 4 per 100 person-years by July 1984. Few infections occurred after 1987, and by that time, 50% of the cohort had become infected. Median seroconversion dates for subgroups of all seropositives ranged from July 1980 to December 1983, depending on the dose and type of fac tor concentrate. Median dates in Europe ranged from September 1981 to March 1983 and reflected the use of products manufactured from America n plasma. Infection incidence apparently peaked about the same time th at public health interventions were introduced to reduce transmission. These interventions, including heat treatment of factor concentrates and deferral of high-risk donors, have prevented HIV-1 infection from becoming endemic among younger birth cohorts of persons with hemophili a.