Interaction between neonatal vitamin A supplementation and timing of measles vaccination: A retrospective analysis of three randomized trials from Guinea-Bissau

Highlights • Early measles vaccine and neonatal vitamin A supplementation may become policy in low-income countries. • Vaccines and vitamin A may interact. • In children who received early measles vaccine, neonatal vitamin A was associated with 5-fold higher overall mortality. • Implementation of both policies at the same time may lead to increased child mortality. • Co-packaging of child health interventions should be investigated for the effect on overall mortality.