CD4, Viral Load Response, and Adherence Among Antiretroviral-Naive Breast-feeding Women Receiving Triple Antiretroviral Prophylaxis for Prevention of Mother-to-Child Transmission of HIV in Kisumu, Kenya

Background: Health benefits and survival of an exclusively breast-fed infant is dependent on the mother's health; thus, the need for antiretroviral (ARV) intervention for prevention of mother-to-child transmission (PMTCT). Achieving maternal health benefits from these regimens requires adherence to the treatments and close monitoring. We evaluated virologic, immunologic responses, and adherence among women receiving maternal triple ARV prophylaxis consisting of lamivudine/zidovudine and nevirapine or nelfinavir in the Kisumu Breastfeeding Study. Methods: We analyzed baseline demographic data, trends in CD4(+) count, and viral load (VL) at enrollment (32-34 weeks gestation), delivery, 14 and 24 weeks postpartum among 434 women who remained in the study at 24 weeks postpartum. Adherence rates were determined using pill counts reinforced by self-report and drug calendar. We dichotomized adherence as >= 95% versus <95%. Results: Among the 434 women, 84% (n = 366) had adherence >= 95%. The proportion of women with undetectable VL (<400 copies/mL) increased from 6% at baseline to 79%, and that of those with CD4(+) count <250 cells per microliter decreased from 23% (100) at baseline to 5% (22) at 24 weeks postpartum. In discrete-survival model, time to achieving VL suppression was associated with baseline VL <5.0 log copies per milliliter, parity >= 2, and use of nelfinavir-versus nevirapine-based ARV. Association between undetectable VL with duration of therapy (P < 0.0001) and adherence with suppression of VL (P = 0.001) was observed. Conclusions: High baseline VL and short exposure to ARVs for PMTCT are risk factors for failing to achieve undetectable VL. These findings support the new WHO guidelines for early initiation of ARV prophylaxis for PMTCT for maximal reduction of maternal VL.