Introduction and objective Immunization of preterm infants is recommended for all infants after the chronological age of 2 months. Immunization of preterm infants has been generally considered safe, effective and particularly necessary. However, apnoea and cardiovascular events after immunization have been reported in preterm infants. The objective of this study is to observe if preterm infants develop minor and/or severe events after the first 3 immunizations in a non-clinical setting.

Methods As part of a larger study, parents of infants born <32 weeks of gestation and/or birth weight <1500 gram were asked to prospectively observe their infants for 48 hours after the first 3 immunizations (DTaP-IPV-Hib (−HepB) + PCV7) by standardized questionnaires (RIVM). Data were compared with published side-effects, observed in term infants.

Results In total 72 questionnaires of 24 preterm infants (median GA 30 w, BW 1280 gr) were reviewed. Local reactions occurred after 29.2% of immunizations, hyperthermia <38.5°C was observed after 11%, fever >38.5°C was never observed, 18% of the infants had a changed feeding pattern, 47.3% had a changed sleeping pattern. Vomiting, diarrhoea, apnoea and cardiovascular events were not reported by parents. 20.8% of the immunized infants received antipyretic drugs. None of the infants had to be admitted to a hospital.

Conclusions Preliminary data of 24 preterm infants who received the first 3 immunizations in a non-clinical setting show minor events comparable with a term healthy population. Parents did not observe severe events like apnoea and cardiovascular events.