Human immunodeficiency virus type 1 subtypes in cohort of infected patients, Saint-Etienne, France, from 1984 to 2003

The authors had for aim to study the distribution of HIV-1 subtypes in a cohort of HIV-1 positive patients in the University hospital of Saint-Etienne, France, and to describe the epidemiological characteristics of patients infected with a non-B subtype strain. An epidemiological study was made on 271 HIV-1 positive patients followed up in the Infectious Diseases Department over 20 years. All patients sample were subtyped by serotyping and some samples were also tested by genotyping. Two hundred and sixty-four patients (191 men and 73 women) were found infected by an HIV-1 strain belonging to the M group. After combining serotyping and genotyping results, 195 patients were found infected by a B subtype and 69 by a non-B subtype. Most of the latter strains belonged to an A subtype or related ones. The following factors were shown to be linked to an infection by a non-B strain: being born abroad, having contracted the infection though heterosexual practice, and being a woman. The incidence of non-B strains increased regularly over time (to reach more than 40% in 2003). This progression was especially noted for men born in France with risky sexual behaviour. These results indicate that more than 40% of HIV-1 new cases detected in the Saint-Etienne area are related to non-B strains and that strains of A and related subtypes are common in the local population with risky sexual behaviour.