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.

We experienced an unexpected cluster of deaths among boys in the VAS arm, which could be due to chance, but we decided to stop randomizing boys to OPV or VAS. Very recent evidence has suggested that low-birth-weight boys may benefit from BCG at birth as well. Hence, we have obtained ethical permission to continue the trial with randomization of boys to OPV or OPV plus BCG.

Inclusion Criteria:

• Low-birth-weight infants (<2500 g)

Exclusion Criteria:

• Already received BCG/OPV
• Overtly sick or have malformations at the time of enrolment
• Clinical signs of vitamin A deficiency (very unlikely)