Supplementary Material for: Randomized Controlled Trial on the Effects of Morning versus Evening Primary Vaccination on Episodes of Hypoxemia and Bradycardia in Very Preterm Infants
2019-08-08T07:03:43Z (GMT) by
Background: Hypoxemia and bradycardia occur frequently in preterm infants, but are incompletely understood. They are more prevalent during infections and following immunization. Data on adults suggested an increased immune response if subjects slept following vaccination, suggesting an interaction between circadian rhythm and the immune system. Whether this holds true for preterm infants with their less well-established circadian rhythm is unclear. Objective: Do infants born at 26–30 weeks’ gestation and having received their first routine hexavalent vaccination in the morning have a lower cardiorespiratory event rate (CER) after vaccination than those receiving it in the evening? Methods: Twenty-six infants were randomized to an evening versus morning vaccination group in a pilot and main study with 10 and 16 participants, respectively. Pulse oximeter saturation, actigraphy, and rectal temperature were obtained for 24 h before and after vaccination. Blood samples for vaccination titers were taken before vaccination and during a follow-up examination in our outpatient clinic; another blood sample was taken 24 h after vaccination to determine inflammatory markers. Results: Vaccination led to an increase in CER in both groups, but there was no difference in CER between the morning and evening groups. Vaccination titers for Bordetella pertussis were increased in both groups, with no difference in inflammatory markers 24 h after vaccination. Body temperature increased in both groups after vaccination. Participants in the evening group slept longer after vaccination. Conclusions: We did not identify a difference in CER between morning and evening vaccination but could confirm increased body temperatures and vaccination titers following vaccination.