Recent Increase in HIV Rate by Age, Cohort, Period Analysis of Surveillance Data Suggests Changes in HIV Epidemiology in Poland

Abstract

To interpret the gradual increase in HIV detection rate in Poland during 1993-2007, separating effects due to epidemic maturation from effects possibly due to new outbreaks or implemented measures. Data from routine HIV/AIDS case-based surveillance reported until the end of 2007 (HIV cases) or 2008 (AIDS cases) was used. Cases aged 15 or above at the time of report of HIV infection were included. Age, cohort and period effects were analyzed using Poisson based model with intrinsic estimator, adjusting for sex and late presentation. We showed no calendar period effect from 1996 until 2005-2007, when a 21% significant increase over the average level occurred. Cohorts born in 1965-1980 are the most affected and the risk is above average for ages 18-47. Until recently the increase in HIV detection rate was due to maturation of epidemic, with HIV affected cohorts replacing older unaffected ones (no calendar period effect). The recent increase coincided with increased testing in general population and increased prevalence in diagnostic testing of men who have sex with men, suggesting important changes in HIV epidemic in Poland.