Follow up of Thai Adult Volunteers With Breakthrough HIV Infection After Participation in a Preventive HIV Vaccine Trial

Prospective cohort study of the clinical course of HIV-1 infection occurring after candidate HIV-1 vaccination (breakthrough infection) with ALVAC-HIV (vcP1521) and AIDSVAX B/E in reference to study NCT00223080 RV144. This study will enroll volunteers who become HIV-infected during the course of follow up in a phase III preventive HIV vaccine trial conducted in Rayong and Chon Buri, Thailand. Volunteers will be enrolled in this protocol to provide additional long-term follow up to establish whether differences in viral load after infection (comparing vaccine to placebo) are associated with altered disease outcomes, as well as provide more detailed immunologic and virologic assessment of these volunteers.

After enrollment in RV152, follow-up visits were scheduled at 0, 1, 3, and 6 months, and every 3 months thereafter. After month 12, CD4+ T cell counts and viral load were obtained at 6-month intervals until the CD4+ T cell count declined to <350/ul or highly-active antiretroviral therapy (HAART) was initiated, at which time CD4+ T cell counts and viral load were obtained every 3 months. Peripartum antiretroviral drugs given for prevention of mother-to-child-transmission was not considered a study endpoint, however HAART initiated during pregnancy and continued post-partum was counted. After a single CD4+ T-cell count < 350/ul a second sample was requested about 2 weeks later, and if the confirmatory measurement was >350/ul, a study endpoint was not registered and the volunteer resumed a normal visit schedule. A single genital fluid collection for viral load was obtained at the first RV152 visit. Clinical and laboratory data from RV144, including CD4+ T-cell and HIV-1 plasma viral load measurements, were linked to RV152 to inform primary and secondary protocol analyses as well as volunteer care and treatment.