Is there a difference in the efficacy of peripartum antiretroviral regimens in reducing mother-to-child transmission of HIV in Africa?

There are positive reports about the ability of antiretroviral agents to prevent mother-to-child transmission (MTCT) of HIV. The authors undertook a pooled analysis of African breast-feeding mothers from clinical trials of various antiretroviral regimens to directly compare their efficacy in lowering the prevalence of MTCT 6 weeks postpartum. A total of 3465 live-born singleton infants participating in 6 randomized clinical trials made up the study population. There were 2 West African zidovudine (ZDV)/placebo trials; 2 regimens of ZDV + lamivudine (3TC) and placebo (pre-/intra-/ postpartum and intra-/postpartum); nevirapine (NVP) and ZDV + 3TKC; NVP and ultra-short ZDV; and a vitamin A trial as a placebo arm. Peripartum HIV infection was diagnosed from a positive RNA or DNA polymerase chain reaction test before 2 months of age. In multivariable logistic regression analysis using placebo for comparison and adjusting for numerous factors (maternal CD4 cell count, breast feeding, low birth weight, geographic area), the lowest rates of MTCT 6 weeks postpartum were observed with ZDV + 3TC pre-/intra-/postpartum with an adjusted odds ratio (AOR) of 0.23. Next most effective, in declining order, were ZDV + 3TC intra-/postpartum (AOR, 0.49); antenatal ZDV short (AOR, 0.55); and NVP (AOR, 0.60). Compared with NVP, only the longest regimen of ZDV + 3TC was significantly more effective (AOR, 0.39). The risk of MTCT was not influenced by cesarean delivery or gender on univariate analysis. In multivariable analysis, the 6-week rate of MTCT was significantly associated with the maternal CD4 cell count. These findings are consistent with current World Health Organization guidelines that consider single-dose NVP and short-course ZDV to be equivalent regimens. Also evident from this study is that the regimen of ZDV + 3TC is more effective than any single antiretroviral agent.