The characteristics of transmitting and non-transmitting women in the study and the neutralization IC50s of their plasma and BMS.

aPlasma neutralization assays were performed at a starting dilution of 1∶100; an IC50 of 50 was assigned in cases where 50% neutralization was not achieved.bBMS neutralization assays were performed at a starting dilution of 1∶20; an IC50 of 10 was assigned in cases where 50% neutralization was not achieved.cViral Load.dIndicates week since delivery when infant was first HIV-1 DNA positive.eIndicates time-point after delivery at which BM sample was obtained.fQ461.d1.gNot done.hNot applicable.iBelow detection.