Purpose To report the immunisation program undertaken by a large tertiary neonatal intensive care unit (NICU). In addition, to describe the characteristics of the infants who will need to be immunised.

Aims To quantify and evaluate the administration of the routine childhood primary vaccination schedule in a NICU.

Methods Audit of the paper record of vaccinations administered to inpatients in the NICU from January 2001 until November 2013. Analysis was made based on gestational age, chronological age at time of administration of vaccine and type of vaccine received.

Results Total of 321 vaccines administered from January 2001 to November 2013.

Mean average of 31 vaccinations per year: minimum 24 (2001), maximum 40 (2010). Mean average of 2.42 vaccinations administered per month.

For all preterm (gestation <37 weeks) patients that received the first ‘6in1’ vaccination while an inpatient (n = 291): mean gestational age = 27.3 weeks (SD 2.0); median gestational age = 27.1 weeks; minimum gestational age 23.9 weeks; maximum gestational age = 36.7 weeks. The mean chronological age at time of vaccination = 9.4 weeks.

For all preterm patients that received the second ‘6in1’ vaccination while an inpatient (n = 18): mean gestational age = 25.8 weeks (SD 1.7); median gestational age = 25.3 weeks; minimum gestational age = 23.9 weeks; maximum gestational age = 29.3 weeks. The mean chronological age at time of vaccination is 18.4 weeks.

For all term (gestation >37 weeks) that received the first ‘6in1’ vaccination while an inpatient (n = 12): mean gestational age = 39.9 weeks (SD 1.6); median gestational age = 40.1 weeks; minimum gestational age = 37.6 weeks; maximum gestational age = 42.3 weeks. The mean chronological age at time of vaccination is 9.3 weeks.

Conclusion Successful immunisation of babies admitted to the NICU is possible regardless of gestational age. Infants born at 27 weeks are likely to require first immunisation in hospital and those born at 25 weeks gestation are likely to remain in hospital in time for their second ‘6in1’ vaccination.