The Natural History of Untreated HIV Infection in Lima, Peru: Implications for Clinical Trial Endpoints for CTL Based HIV Vaccines

Abstract

Most candidate HIV vaccines are directed at priming memory T cell responses and are being evaluated on their effects on post acquisition viremia and/or disease progression. These vaccines are being studied in areas of high HIV-1 prevalence. As such, we evaluated the frequency of CD4+ T cell decline and time course of opportunistic infections of patients presenting at a major metropolitan hospital in Lima, Peru, an area where such candidate vaccines are being tested. We examined 92 patients with untreated HIV-1 in calendar year 2002: 35% presented with CD4+ T cell counts of 400 cells/mm3, 30 of 92 patients presented with overt AIDS, 6 were without an AIDS defining OI but CD4 counts 0.5). Among persons presenting with CD4 counts >250 cells/mm3, the median time to first OI was 3.5 years. If clinical endpoints are required to evaluate the clinical effectiveness of T cell based vaccines, extended clinical follow-up of subjects enrolled in such trials will be required.