Effect of perinatal short-course zidovudine on the clinical and virological manifestations of HIV-1 subtype E infection in infants

Background: The perinatal short-course zidovudine (ZDV) chemoprophylaxis that can reduce HIV-1 vertical transmission by 51% has been widely practiced in developing countries such as Thailand because of its simpler and less cost. Objectives: To investigate the effects of short-course regimen of oral ZDV for prophylaxis of HIV-1 subtype E vertical transmission among 'break-through' HIV-1 infected infants. Study design: The study analyzed clinical and virological outcomes of 80 infants, whose mothers received ZDV prophylaxis starting at 36 weeks gestation (group Z) and 37 infants whose mothers never received anti-retroviral drugs (group C), at the ages of 1-2, 4-6, and 12 months. Results: Of the 12 HIV-1 infected infants, 5/7 (71.4%) from group Z and 1/5 (20%) from group C progressed to a symptomatic clinical stage by the age 4-6 months. The intersample nucleotide distance of HIV-1 pol reverse transcriptase (RT) sequences of isolates collected at age of 1-2 months from group Z was significantly higher than that from group C (3.34 and 2.92%, P = 0.02). All twelve virus isolates from infected infants were non syncytium inducing (NSI) and macrophage tropic strains; and 5/6 (83.3%) viruses from symptomatic infants were also T-tropic viruses. The symptomatic infants also had significantly higher HIV-1 nucleic acid quantitation than asymptomatic infants. Conclusion: Our results preliminary suggested that infected infants who were perinatally exposed to ZDV may have a more rapid early disease progression with unfavorable viral manifestations than those without exposure to antiretroviral drug. (C) 2002 Elsevier Science B.V. All rights reserved.