Flynn PM, Taha TE, Cababasay M, et al. - On assessing the correlation of maternal viral load (MVL) and CD4 cell counts with breastfeeding HIV transmission, researchers identified that risk of infant HIV-1 infection is increased in women receiving mART, increased MVL and decreased CD4 cell counts during breastfeeding.

• Randomized were breastfeeding mothers with HIV infection who did not qualify for antiretroviral therapy (ART) based on country-specific guidelines at the time of the Promoting Maternal-Infant Survival Everywhere trial and their uninfected neonates to either maternal ART (mART) or infant nevirapine prophylaxis (iNVP) postpartum.

• The two arms had similar proportions of HIV transmission (< 1%). Enrolled were 2,431 mother–infant pairs.

• No significant association of baseline MVL and CD4 cell counts was observed with infant HIV-1 infection.

• In the mART arm, significant association of time-varying MVL, as well as of time-varying CD4 cell counts, was observed with infant HIV-1 infection.