Kumar A, Giorgi EE, Tu JJ, et al. - An increase in new pediatric HIV infections has recorded by nearly 150,000 every year, despite widespread, effective use of antiretroviral therapy (ART) among HIV infected pregnant women. Interestingly, reports describe transmission of HIV in less than half of HIV-infected pregnant women in the absence of ART, suggesting natural immune protection of infants from virus acquisition. Researchers aimed at ascertaining the influence of maternal plasma autologous virus neutralization responses on mother-to-child transmission (MTCT) via comparing untreated, HIV-infected transmitting and non-transmitting mothers with respect to their plasma and bnAb neutralization sensitivity of the circulating viral population present at the time of delivery. While transmitting and non-transmitting women did not differ significantly in the ability to neutralize their own circulating virus strains, there were specific genetic motifs enriched in variants from transmitting mothers that were linked with resistance to broadly neutralizing antibodies (bnAbs), indicating acquired bnAb resistance to be a common feature of vertically-transmitted variants. Per these findings, thay support enhancement of plasma neutralization responses in HIV-infected mothers through passive or active vaccination to further drive selection of variants that could be vertically transmitted, and emphasize practicing caution in the use of passive bnAbs for HIV-1 prophylaxis or therapy during pregnancy.