These findings from the ongoing Promoting Maternal and Infant Survival Everywhere (PROMISE) study support the World Health Organisation (WHO) guidelines introduced in 2015 that recommend lifelong antiretroviral therapy for all pregnant and breastfeeding women living with HIV.
Researchers found that both three-drug maternal antiretroviral therapy and daily infant nevirapine were safe and effective at preventing HIV transmission during breastfeeding.
Overall, infant mortality in the study was extremely low, with nearly all babies surviving their first year of life.
"Maternal antiretroviral therapy safely minimises the threat of HIV transmission through breast milk while preserving the health advantages of breastfeeding, as the high infant survival in this study underscores," Fauci said.
Also Read
PROMISE, which began in 2010, is a multi-component study that aims to determine how best to safely reduce the risk of HIV transmission from HIV-infected women to their babies during pregnancy, delivery and after childbirth, while preserving the health of both mother and child.
HIV-infected mothers in areas that lack safe, clean water may be encouraged to breastfeed because of the health benefits for the infant and the risk for infants from mixing formula with an unsafe water supply.
Breastfeeding helps prevent malnutrition, and antibodies from breast milk protect babies against potentially life-threatening diarrhoeal and respiratory infections.
The researchers enrolled 2,431 pairs of HIV-infected mothers and their HIV-uninfected infants at clinical research sites in South Africa, Malawi, Tanzania, Uganda, Zambia, Zimbabwe and India between June 2011 and October 2014.
The rate of perinatal transmission did not differ between the two study arms and was very low - 0.3 per cent at 6 months of age and 0.6 per cent at one year of age.
The longer an HIV-infected mother breastfeeds, the greater the risk for HIV transmission to the infant. In comparison, in the absence of any intervention, rates of HIV transmission from a HIV-infected mother to her child during either pregnancy, labour, delivery or breastfeeding historically have ranged from 15 to 45 per cent, according to WHO.