Don't wait, vaccinate: evaluation of routine vaccination administration and reactogenicity in preterm infants.

Objective: To evaluate the incidence of cardiorespiratory events in preterm infants when administering the 2-month vaccine series all at once compared to spreading vaccines over multiple days.

Study Design: This single-center, retrospective cohort study from 2019-2022 included preterm neonates receiving 2-month vaccinations. The primary outcome was incidence of cardiorespiratory events from time of initial vaccine administration up to 48 h after final administration. Univariate analysis was performed to identify predictors of primary outcome.

Results: There were 127 patients (pre-practice change n1 = 52, post-practice change n2 = 75) included with no difference in the number of cardiorespiratory events between groups. Predictors of severe event included younger gestational age, smaller birth weight, shorter birth length, and greater cardiorespiratory events at baseline. Vaccine schedule interruptions occur more often when administration is spread over multiple days.

Conclusion: Administration of 2-month vaccinations all at once was not associated with increased cardiorespiratory events and prevents interruptions to vaccine schedule.