Study also confirms condom use significantly reduces risk of HIV
infection The level of HIV-1 in the blood of an HIV-infected
partner is the single most important factor influencing risk of
sexual transmission to an uninfected partner, according to a
multinational study of heterosexual couples in sub-Saharan
Africa. The study, published in The Journal of Infectious
Diseases and available online, calculated the risk of HIV-1
transmission per act of sexual intercourse and found the average
rate of infection to be about 1 per 900 coital acts. The
findings also confirmed that condoms are highly protective and
reduce HIV infectivity by 78 percent. James P. Hughes, PhD, and
colleagues at the University of Washington and the Fred
Hutchinson Cancer Research Center, in Seattle; the University of
Witwatersrand in South Africa; the University of Nairobi and
Kenyatta National Hospital, in Kenya; and the Rwanda-Zambia HIV
Research Group conducted a study that included 3,297 HIV-
discordant couples (where one person is HIV-