Cost-effectiveness analysis of infant feeding strategies to prevent mother-to-child transmission of HIV in South Africa

Abstract

Despite increasing availability of perinatal interventions to prevent mother-to-child transmission (MTCT) of HIV in South Africa, MTCT remains high due to breastfeeding. To inform policy decisions in the country, cost-effectiveness of alternative infant-feeding interventions was conducted. Mathematical modelling was used to simulate post-natal transmission and mortality due to infant feeding in a hypothetical cohort of 1 000 HIV-exposed infants. Lifetime costs to the health system were calculated for each strategy. Interventions compared with current practice were: increasing coverage of extended nevirapine prophylaxis (ENP) to infants from 30% (base case) to 60% without changing current feeding practices; actively supporting breastfeeding with ENP to infants for 12 months; and actively supporting exclusive formula (replacement) feeding for 6 months. HIV-free survival at 24 months and disability-adjusted life years (DALYs) averted were estimated for typical rural and certain urban settings. Base-case analysis revealed that expanding coverage of nevirapine prophylaxis with breastfeeding is cost-saving and improves HIV-free survival. Changing feeding practices is beneficial, depending on context. Breastfeeding is dominant (less costly, more effective) in rural settings, whilst formula feeding is a dominant strategy in urban settings. Cost-effectiveness was most sensitive to proportion of women on lifelong antiretroviral therapy (ART) and infant mortality rate (IMR). When >55% of women are on ART, breastfeeding dominates in the urban settings modelled, whilst formula feeding is cost-effective in rural settings when IMR ≤ 45/1000. The study concludes that strategies to support breastfeeding are essential. Strengthening health systems is critical to ensure optimal nevirapine delivery during breastfeeding. A case can be made for formula feeding or breastfeeding in HIV-infected women in specific contexts.