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Lancet. 1994 Apr 16;343(8903):943-6.

Slower heterosexual spread of HIV-2 than HIV-1.

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Department of Cancer Biology, Harvard School of Public Health, Boston, MA 02115.


Because of the similar virological properties of HIV types 1 and 2, HIV-2 was assumed to be as infectious and capable of inducing AIDS as HIV-1. Seroepidemiological studies have shown significant rates of HIV-2 infection in West Africa, and surveys from other regions of the world indicate that the spread of HIV-2 infection continues. However the pathogenic potential of HIV-2 is considered to be lower than that of HIV-1. It is therefore important to understand the transmission properties of HIV-2 and its contribution to the AIDS pandemic. Since 1985, we have prospectively studied 1452 registered female prostitutes in Dakar, Senegal, with sequential evaluation of their antibody status to HIV-1 and HIV-2. During the study the overall incidence of HIV-1 and HIV-2 was the same (1.11 per 100 person-years of observation [pyo]). However, the annual incidence of HIV-1 increased substantially: there was a 1.4-fold increased risk per year and thus a 12-fold increase in risk over the entire study period. The incidence of HIV-2 remained stable, despite higher HIV-2 prevalence. In our population the heterosexual spread of HIV-2 is significantly slower than that of HIV-1, which strongly suggests differences in the viruses' infectivity potential.


Between February 1985 and February 1993 in Dakar, Senegal, the Social Hygiene Clinic screened 1452 registered female prostitutes (5608 samples) for sexually transmitted diseases, including HIV-1 and HIV-2. The overall prevalence rate stood at 11.3% for HIV-2 while it was 6.2% for HIV-1. 12 women (0.8%) tested positive for HIV-1 and HIV-2. Health workers followed the 1277 women who were initially HIV seronegative to determine seroconversion. 46 of these women seroconverted to HIV-2 and another 46 seroconverted to HIV-1. Overall incidence of HIV-2 and HIV-1 was 1.11 per person years of observation (pyo). Eight women (incidence = 0.19 per 100 pyo) seroconverted to both HIV-2 and HIV-1. When the researchers controlled for age, nationality, years of registered prostitution, calendar year, and time in study, the relative risk for HIV-2 infection each year did not change. On the other hand, there was a significant 1.43 annual increase in the risk for HIV-1 infection (p .002), indicating a 12-fold increase in the risk of HIV-1 infection over the study period. These findings suggest that the 2 viruses have a distinctly different in-vivo biology and that HIV-2 has a lower infectivity than does HIV-1.

[Indexed for MEDLINE]

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