Monitoring the dynamics of the HIV epidemic using assays for recent infection and serotyping among new HIV diagnoses: experience after 2 years in France.

Background: New tools to better monitor dynamics of human immunodeficiency virus (HIV) transmission are needed.
Methods: National surveillance of newly HIV diagnoses included the collection of dried serum spots to identify both recent infections (<6 months) and HIV serotypes. Multivariate analyses were used to identify factors associated with recent infection and infection with non-B subtypes.
Results: Between 2003 and March 2005, 7902 new HIV diagnoses were reported. The overall proportion of recent infections was 24.9% (95% confidence interval, 23.8%-26.0%) and was highest among men who have sex with men (MSM; 46%). Recent infection was associated with being an MSM, <30 years old, of French nationality, and living in Paris. Nearly half of newly HIV-1 diagnoses were with non-B subtypes. The highest proportion of non-B infections was reported among African heterosexual persons (81%), but important proportions were reported among French heterosexual persons (34%) and MSM (12%). Being infected by a non-B subtype was independently associated with being African, <30 years old, heterosexual, and living in Paris. The proportion of HIV-2 infection was 1.9%, and 11 cases of HIV-1 group O infection were identified, mainly among West Africans.
Conclusions: There is evidence of high levels of HIV transmission among MSM in France and transmission of non-B subtypes within the indigenous French population.