Risk of Acquiring Sexually Transmitted HIV in Africa One in 588, Study Shows
The risk of HIV transmission in Africa from a single sexual encounter involving one infected person is one in 588, according to a study of heterosexual couples in Africa, the AP/Philadelphia Inquirer reports. Researchers from Johns Hopkins University studied 174 monogamous couples in Rakai, Uganda, in which one partner was HIV-positive and the other was not. Couples were given condoms but "usually did not use them." Researchers found that couples typically had sex between nine and 10 times a month, and "over time," 38 people became infected with HIV. From these findings, researchers estimated that among Africans who "do not use condoms and who have sex regularly with one infected partner," the risk of transmitting HIV during each sexual encounter is one in 588. Researchers are unsure whether risk estimates are different in areas outside of Africa, but CDC AIDS Chief Dr. Helene Gayle said that the study provides a "general estimate" of HIV transmission risk. Additional findings from this study include:
- Infected teenagers are three times more likely to "spread HIV" to others during each sexual encounter compared to people over 40.
- The risk of HIV transmission from an infected woman to an uninfected man is one in 454. The risk for transmission from an infected man to an uninfected woman is one in 769. This discrepancy was "not large enough to be statistically meaningful, and many have assumed that HIV spreads more readily from men to women than vice versa."
- The risk of transmission "depends greatly" on the infected person's viral levels. Among those with viral levels less than 1,700 copies per milliliter of plasma, the risk is one in 10,000, while among those with levels above 38,500, the risk is one in 294. This finding supports the belief that widespread use of AIDS drugs that lower viral levels "will slow the spread of the disease."
- Risk of HIV transmission "appears to be the same" for different viral subtypes.
- None of the circumcised men in the study contracted HIV (Haney, AP/Philadelphia Inquirer, 2/9).