Risk factors for adverse events after vaccinations performed during the initial hospitalization of infants born prematurely.

INTRODUCTION: There are significant delays in implementing vaccination among preterm infants.

OBJECTIVES: Description of the frequency and kinds of adverse events following immunization in preterms. Establishment of the group of preterms who will distinctively be susceptible to adverse events.

MATERIALS AND METHODS: Demographical, clinical data and the occurrence of adverse events after DTaP, HIB and pneumococcal vaccination among preterms during their initial hospitalization were prospectively collected with the use of an electronic data form between 1st June 2011 and 31st May 2015. The analysis was conducted on 138 patients. The groups were divided according to maturity (I: ≤ GA 28w n=73 and GA 29-36 w n=65).

RESULTS: There were no statistically significant differences between the groups in the occurrence of adverse events. Out of the total group, following vaccination apnoea developed in 6 newborns (4%) and activity dysfunctions were observed in 13 newborns (10%). The occurrence of apnoea after vaccination positively correlated with the time of non-invasive ventilation and the occurrence of late infection. There were no statistically significant demographical or clinical risk factors for the development of activity dysfunctions following vaccination.

CONCLUSIONS: Term vaccination in clinically stable preterm infants is a safe medical procedure. However, long-term non-invasive respiratory support and late infections are risk factors for apnea following vaccinations. In these patients vaccinations should be considered during hospitalization.