Breast-Milk Shedding of Drug-Resistant

Single-dose nevirapine reduces intrapartum human im-munodeficiency virus 1 type (HIV-1) transmission but may also select for nonnucleoside reverse-transcriptase inhibitor (NNRTI) resistance in breast milk (BM) and plasma. Among 32 Zimbabwean women, median 8-week postpartum plasma and BM HIV-1 RNA levels were 4.57 and 2.13 log10 copies/ mL, respectively. BM samples from women with laboratory-diagnosed mastitis (defined as elevated BM Na+ levels) were 5.4-fold more likely to have HIV-1 RNA levels above the median. BM RT sequences were not obtained for 12 women with BM HIV-1 RNA levels below the lower limit of detection of the assay used. In 20 paired BM and plasma samples, 65% of BM and 50 % of plasma RT sequences had NNRTI-resis-tance mutations, with divergent mutation patterns. In 2003, 1600,000 infants were infected with HIV-1 throug