Objective:  To determine if vaccinations administered in the neonatal intensive care unit (NICU) were administered following Centers for Disease Control and Prevention guidelines while assessing for adverse reactions in the 48 hours post-vaccination.  
Study Design:  Retrospective cohort study of infants who received Diphtheria-Tetanus-Pertussis, inactivated Polio, Hepatitis B vaccines during NICU admission from February 2016 to January 2017 with a total of 337 immunization events reviewed. Data were assessed to determine vaccination delay according to recommended schedules as well as rate of adverse events. Knowledge base and attitudes were evaluated through a questionnaire administered over a three-week period to NICU care providers.
Results:  Of the 337 immunization events reviewed, 256 vaccines were administered within 7 days of the recommended vaccination schedule, leaving 24% (n=81) administered outside of this schedule. Taking into account weaning of respiratory support and deterioration of respiratory status in the 48 hours prior to vaccination, total adverse event rates for the remaining 312 immunization events were 2% (n=7). Questionnaire showed many providers felt adverse events are commonplace following vaccination and highlighted a possible gap in knowledge of recommended vaccination guidelines.
Conclusions:  This study suggests neonates admitted to the NICU are at risk for vaccination delay. Immunizations have a low rate of adverse events, thus confirming safety. Factors that may increase adverse events post-immunization include coincidental worsening of overall status and recent wean in respiratory support. Further studies are needed to examine best practices to promote improved vaccination in the NICU.