Vertical transmission of HIV through breast milk most likely to occur soon after birth

Researchers have found that the time of greatest risk for transmission of HIV through breast milk is during the early postpartum months (JAMA1999;282:744-9). In a study conducted between 1994 and 1997, 672 infants were followed for two years in Malawi. The infants had tested negative for HIV infection at birth and had been born to women infected with HIV who had not been treated with antiretroviral drugs during or after pregnancy.

The frequency, timing, and risk factors for the transmission of HIV through breast milk were measured. Infants were followed at a postnatal clinic. The …