HIV incidence estimates among women of childbearing age in the area around Paris, France: no evidence for any effect of age or time.

ABSTRACT

OBJECTIVE: To explore whether there are any age or time effects on the HIV incidence rate among women of childbearing age in the area around Paris (France). DESIGN: Three seroprevalence surveys were conducted among pregnant women in the Paris area (PREVAGEST) during three periods (1990-1991, 1992-1993, 1994-1995); their data were used to derive HIV incidence estimates with Ades and Medley's method. To assess the power of our study, data were also simulated with a demographic model under different assumptions for HIV-incidence rates. RESULTS: No age or time effect was detected on HIV incidence in the Paris area during the period from 1990 to 1995. Analysis of simulated surveys showed that with the sample size of the PREVAGEST surveys, the method was able to detect an age or time effect with a relative risk of about 2.5 between age groups or periods. CONCLUSION: We conclude that the method is applicable to our data. If any existed, age or time effect was quite likely no higher than 2.5. As we previously reported using another method, incidence of HIV infection among women of childbearing age in the Paris area can be estimated at 0.74/1,000 per year (95% confidence interval, 0.62-0.87) from 1990 through 1995.