A study in the journal Lancet Infectious Diseases calls into question the criteria used by researchers to assess the risk of HIV transmissions through heterosexual intercourse. Researchers had estimated that an act of unprotected sex between serodiscordant heterosexuals has a one in 1,000 chance of viral transmission, but the criteria don't include such risk factors as the male partner being uncircumcised, either partner having genital lesions, or fluctuations in the HIV-positive partner's viral levels. These can raise the transmission risk between several times and several hundred times, according to the new analysis.
