Incubation period of HIV-1 in perinatally infected children

Objectives: To estimate the distribution of the incubation period of HIV-1 among perinatally infected children and to test the hypothesis that this distribution has been changing over time. Design: An analysis of 190 perinatally HIV-1-infected children born between 1986 and 1997 in eight medical centers in New York City to women enrolled in a prospective cohort study. Methods: Non-parametric Kaplan-Meier method and parametric survival analysis. Results: Using the Kaplan-Meier method it was estimated that among perinatally HIV-1-infected children, 48% [95% confidence interval (CI), 41-56] developed AIDS by 3 years of age after which the rate was less than 3% per year. Using a parametric survival analysis for extrapolation, it was predicted that 33% (95% CI, 23-43) would remain AIDS-free at 13 years of age. Median age at onset of AIDS was estimated to be 4.1 years (95% CI, 1.9-6.4) by parametric survival analysis. The year of birth was significantly associated with AIDS-free survival, suggesting an increase in the time to AIDS over the years. This association remained significant (P = 0.03) after adjustment for those maternal characteristics that have also changed over time: timing of enrollment (prepartum versus postpartum), zidovudine, alcohol, and hard drug (heroin, cocaine or methadone) use during pregnancy. Conclusions: Although a substantial proportion of perinatally HIV-1-infected children develop AIDS very early in life, a significant and increasing percentage of them are expected to survive into adolescence without developing AIDS. Further research is needed to determine the factors associated with the lengthening survival to AIDS.