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

HIV vaccines are being developed to both reduce acquisition of infection as well as to reduce post-acquisition viral replication and disease progression. Most efficacy trials of HIV-1 vaccines are being initiated in areas of the world with high HIV incidence, yet there is little published data on the characterization of the clinical course of HIV-1 infection in these regions. 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 candidate HIV-1 vaccines are being tested. We examined 92 consecutive patients with untreated HIV-1 in calendar year 2002 seen at the specialty HIV clinic and evaluated the CD4(+) T cell count and frequency of opportunistic infections over time. Over the course of follow-up, CD4 count decreased by a mean of 31 cells/mm(3)/yr in women and 28 in men (p > 0.5). Among persons presenting with CD4 counts > 250 cells/mm(3), the median time to first OI was 3.5 years and the median time to CD4 count < 200 cells/mm(3) was 4.5 years. The most frequent observed OIs were TB, candidiasis, Pneumocystis pneumonia, Cryptococcus, and nonHodgkins lymphoma. If clinical endpoints are required to evaluate the clinical effectiveness of HIV-1 vaccines, extended clinical follow-up of subjects enrolled in such trials will be required.