HIV-1 diversity in France, 1996-1998

Objective: To study the distribution of HIV-I subtypes in France and to des cribe the characteristics of patients infected with non-B subtypes. Methods: All adults who tested HIV-1 positive on Western blot for the first time in one of the participating laboratories between September 1996 and M arch 1998 were eligible, whether or not they had been diagnosed previously elsewhere. Data on age, sex, country of birth, HIV-transmission group, date s of the last negative and first positive HIV test and clinical stage were collected. Serotyping was performed with a peptide subtype-specific enzyme immunoassay on each plasma sample and genolyping with heteroduplex mobility assay on each non-B serotype-infected patient. Patients characteristics we re compared in B and non-B subtypes. Results: Of the 2168 HlV-positive patients included by 32 laboratories, sub type results were available for 2042. Among those, 73.4% were men, 12.2% bo rn in sub-Saharan Africa, 41.5% infected through heterosexual contact and 6 7.6% in CDC stage A. Among the 2042 patients, 1725 (84.5%) were infected wi th B subtype, Among the 317 non-B subtypes, subtype A was predominant (66.9 %); all other subtypes (C, D, E, F, C, H, O) were present. Factors independ ently associated with a non-B subtype were to be included in the Paris area [adjusted odds ratio (aOR), 1.6; 95% confidence interval (CI), 1.1-2.3], t o be born in sub-Saharan Africa (aOR, 26.0; 95% CI, 17.5-37.8) and to be in fected through heterosexual contact (aOR, 4.2; 95% CI, 2.8-6.4). Conclusions: In France, although B subtype is still predominant, all non-B subtypes are now present. The diversity of HIV strains may affect diagnosti c tests and clinical practice, especially viral load measurements. Moreover , the decreased susceptibility of non-B subtypes to antiretroviral drugs em phasizes the importance of surveillance of HIV diversity. (C) 2000 Lippinco tt Williams & Wilkins.