Our group has consistently found that the major interventions to reduce morbidity and mortality in low-income countries have sex-differential effects. These interventions include BCG vaccine, oral polio vaccination (OPV), and vitamin A supplementation (VAS).

Low-birth-weight (LBW) children constitute the largest high-risk group in low-income countries. According to current policy, they receive OPV at birth. Current evidence suggests that a policy of providing BCG with OPV for girls and VAS instead of OPV for boys at birth may improve survival in LBW neonates. This will be tested in a large randomized trial.