Dual seroreactivity to HIV-1 and HIV-2 in female sex workers in Abidjan, Côte d'Ivoire

To determine the absolute and proportional prevalence of dual seroreactivity to HIV-1 and HIV-2 in female sex workers in Abidjan, to determine risk determinants for this serologic profile, and to describe the associated clinical and immunological characteristics. Cross-sectional study. Confidential clinic for female sex workers in Abidjan. Female sex workers. HIV serostatus, CD4+ counts, women with AIDS, behavioural and sociodemographic characteristics. Among 1209 women tested, the overall HIV seroprevalence was 80%, while the prevalence of dual seroreactivity was 30%. Dual seroreactivity accounted for 38% of all HIV infections. Compared with women reacting to HIV-1 only, dually seroreactive women were significantly more likely to have been in sex work for a longer period, to be aged > or = 20 years, and to charge less money for intercourse. No difference in mean CD4+ count was noted between women with dual seroreactivity (561 x 10(6)/l) and HIV-1-seropositive women (558 x 10(6)/l). Female sex workers in Abidjan had the highest absolute (30%) and proportional rate (38%) of dual seroreactivity yet described in any population. Increased sexual exposure is associated with an increased risk of dual seroreactivity. Although better molecular diagnostic techniques are required, a substantial proportion of female sex workers in Abidjan is likely to be infected with both HIV-1 and HIV-2.