The continuing fall in the number of children becoming infected with HIV is a major public health triumph. Globally, 1.6 million new child infections were averted between 2008 and 2017, an achievement that stems from a steep increase in the percentage of pregnant women living with HIV who receive antiretroviral medicines to prevent mother-to-child transmission of HIV or as lifelong therapy, from 25% in 2008 to 80% in 2017.

However, much remains to be done. Efforts to prevent mother-to-child transmission have been slowed by inconsistent treatment adherence among expectant and breastfeeding mothers living with HIV and by the significant numbers of pregnant and breastfeeding women with undiagnosed HIV. A high risk of HIV acquisition faced by women in Africa during pregnancy and breastfeeding has also been underappreciated.