Background:  To monitor the dynamic of HIV infection in France, a routine incidence testing (EIA-RI assay) has been implemented as part of the national HIV case surveillance, as early as 2003. This analysis presents the first direct estimates of HIV incidence at the country level over recent years.

Methods:  We first performed a calibration analysis for the EIA-RI assay using follow-up measurements from 246 seroconverters. We then adapted the Karon model to calculate the annual number of new infections in various epidemiological subgroups in the French population, based on reported HIV diagnoses detected as recent infections. Data were adjusted for reporting delays and for under-reporting. Missing information for key variables was imputed by multiple imputation. To calculate incidence rates, subpopulation sizes were obtained from the national census and national behavioral studies. Temporal trends in incidence of HIV infection based upon 42,330 diagnoses were compared using weighted least-square regression.

Results:  An estimated 6940 (95%CI:6200 to 7690) persons were newly infected in France during 2008. This led to an overall incidence rate of 17 per 100,000 persons/year. With 3320 (48%) new infections in 2008, men who have sex with men (MSM) contributed dramatically to the overall number of cases. Incidence rate among MSM was 1006 per 100,000 persons/year. Among the 3550 (51%) new infections attributed to heterosexual transmission, foreigners living in France represented 45% (1600), whereas French nationals represented 55% (1950). Intravenous drug users accounted for 1% of new infections. The overall HIV incidence decreased from 2003 (8930 new infections) to 2008, while it remained stable among MSM.

Conclusions:  Over the period 2003 to 2008, our results confirm a disproportionately high contribution of MSM to current HIV transmission. Migration and infections acquired abroad must be accounted to interpret the number of new HIV infections among foreigners in France. Based on this new method applied at a national scale, HIV incidence will be tracked over time in order to monitor the HIV transmission dynamics in the various risk groups of the population and to better target prevention.