[Cardiorespiratory events after first immunization in premature infants: a prospective cohort study]

To investigate whether all preterm infants born before 33 weeks of gestation need cardiorespiratory monitoring due to the risk of cardiorespiratory disturbances following their first vaccination at 2 months of age.

A prospective observational cohort study.

During a period lasting a little over a year, all preterm infants who were being cared for at the neonatal ward of Medical Centre Alkmaar because they had been born before 33 weeks of gestation received their first immunization at the age of 2 months and were subsequently monitored. Infants who had already been discharged by that time were readmitted for this purpose.

In this cohort of 41 premature infants whose mean gestational age was 30.8 weeks (SD: 1.9), 10 of these had a mild decrease in oxygen saturation or bradycardia; three developed a moderate cardiorespiratory event requiring tactile stimulation. The incidence of disturbances was higher in younger and lower-weight infants and those who had experienced more severe morbidity during the neonatal phase. Moderate disturbances only occurred in the infants who had not yet been discharged from hospital after birth.

It is recommended that still-hospitalized premature infants receive their first immunizations under cardiorespiratory monitoring, as events were observed during a period of 0-24 hours thereafter. In premature infants who had already been discharged - mainly because they were less premature or dysmature - immunization without cardiorespiratory monitoring appeared to be safe. Further research is needed for substantiating this strategy.