Impact of birth weight at term on rates of emergency room visits and hospital admissions following vaccination at 2 months of age

► We examined the impact of birth weight on risk of emergency room visit and hospital admission in the immediate three days post vaccination. ► Lower birth weight quintile increased the risk of ER visits in the 24 h following vaccination. ► SGA10 infants had a higher risk of events than non SGA10 infants,-SGA10 children vaccinated before 60 days had a higher risk of events compared to those vaccinated after 60 days.