Comparison of HIV-1 Mother-to-Child Transmission After Single-Dose Nevirapine Prophylaxis Among African Women With Subtypes A, C, and D

The HIVNET 012 trial in Uganda showed that mother-to-child transmission (MTCT) of HIV-1 can be prevented by providing pregnant women and their infants with a single dose (SD) of the antiretroviral drug nevirapine (NVP). Safety and efficacy of 1- or 2-dose NVP prophylaxis for prevention of MTCT have been documented in other studies. We have shown that NVP resistance emerges in some women after SD NVP prophylaxis and that the portion of women with NVP resistance is influenced by HIV-1 subtype. At 6 to 8 weeks after SD NVP NVP resistance was more common in women with subtype C (69.2%) than in women with subtype D (36.1% P < 0.0001) or subtype A (19.4% P < 0.0001).4 Selection of NVP-resistant HIV-1 variants in women after NVP dosing could theoretically lower the efficacy of NVP prophylaxis for prevention of HIV transmission by breast-feeding in the first few weeks after birth. In the HIVNET 012 trial most women were infected with HIV-1 subtype A or D. Risk of MTCT was slightly (but not statistically) higher in women with subtype D. In this report we combined data from the HIVNET 012 and NVAZ trials to compare the risk of MTCT in women with subtype C to the risk of MTCT in women with subtypes A and D in the setting of SD NVP prophylaxis. (excerpt)