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.
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-infectedchildren 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-infectedchildren, 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-infectedchildren 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.