Objective To estimate the incremental cost over 5 years of a policy switch from the Option B to the Option B+ protocol for the prevention of mother-to-child transmission (PMTCT) of the human immunodeficiency virus (HIV). Methods Data from cost studies and other published sources were used to determine the cost, per woman and per cohort (1000 breastfeeding and 1000 non-breastfeeding women), of switching from Option B (maternal triple antiretroviral [ARV] regimen during pregnancy and breastfeeding plus daily nevirapine for the infant for 6 weeks) to Option B+ (maternal triple ARV regimen initiated during pregnancy and continued for life). The variables used to model the different scenarios were maternal CD4+ T lymphocyte (CD4+ cell) count (350-500 versus > 500 cells/mu l), rate of decline in CD4+ cells (average, rapid, slow), breastfeeding status (yes, no) and breastfeeding duration (12, 18 or 24 months). Findings For women with CD4+ cell counts of 350-500 cells/mu l, the incremental cost per 1000 women was 157 345 United States dollars (US$) for breastfeeding women and US$ 92 813 for non-breastfeeding women. For women with CD4+ cell counts > 500 cells/mu l, the incremental cost per 1000 women ranged from US$ 363 443 to US$ 484 591 for breastfeeding women and was US$ 605 739 for non-breastfeeding women. Conclusion From a cost perspective, a policy switch from Option B to Option B+ is feasible in PMTCT programme settings where resources are currently being allocated to Option B.
