Information has been received from a literature article. Background: Preterm infants should receive immunisations according to their chronological, rather than gestational age, however concern about possible adverse events following immunisation (AEFI) in this group often means routine immunisations are delayed. A small number of infants may have apnoea with or without bradycardia temporarily associated with immunisation. The risk factors for and recurrence rate of apnoea with subsequent immunisations are unknown, which makes planning for subsequent immunisations for these highly vulnerable infants difficult. Aim: To determine recurrence rates for apnoea temporally associated with immunisation in preterm and term infants and to explore potential risk factors associated with recurrent apnoea in preterm infants. Method: A retrospective analysis of all apnoea +/- bradycardia AEFIs in preterm and term infants, over a 3-year period from May 2007 to April 2010. Apnoea +/- bradycardia was defined as temporally associated with immunisation if it occurred up to 48 h after immunisation. Results: 7 out of 38 (18%, 95% confidence interval 6-31%) preterm infants with apnoea +/- bradycardia post initial immunisation had recurrent apnoea with subsequent immunisations. Possible risk factors for recurrence included: lower birth weight (p = 0.04) and ongoing hospitalisation for complications relating to prematurity (p = 0.01). No preterm infant with recurrent apnoea had a third episode of apnoea with subsequent immunisation. None of the 8 term infants with a reported apnoea AEFI had recurrence of apnoea with subsequent immunisation. Most infants received B virus vaccine (manufacturer unknown) received the routine vaccines as combination vaccines either: INFANRIX HEXA or INFANRIX-IPV and COMVAX, and PREVENAR, and ROTATEQ, at their 2 and 4 month immunisations. Not all children received ROTATEQ. 38 preterm infants with a median gestational age of 27 weeks had an episode of apnoea following immunisations. Of the 38 preterm infants, 35 had an apnoea following their 2-month immunizations. The other three infants did not have a reported apnoea following their 2-month immunizations. The other three infants did not have a reported apnoea following their 2-month immunizations but suffered apnoea following their 4-month immunisations. One of the infants with apnoea following the 4-month immunisations had suffered a hypotonic hyporesponsive episode (HHE) following his 2-month immunisations. The patient in this report was a female preterm baby (birth weight 735g) with a history of several co-morbid conditions including pancreatic agenesis (requiring an insulin pump), severe intra-uterine growth retardation and a patient ductus arteriosis causing cardiac failure. The patient received her 2-month immunisations when she was 60 days old (8 weeks and 4 days). 2 hours after immunisation the patient experienced frequent brief +/- bradycardia for 24 hours. The patient was not supervised for their subsequent immunisation. The patient received her 4-month immunizations when she was 19 weeks and 5 days old, half a hour post immunization the patient experienced recurrent apnoea. This infant was reported by her parents to suffer an apnoea 30 min after vaccine administration (she was on an apnoea monitor at home and was found to be unresponsive and cyanotic when the monitor alarmed), which lasted up to 2 min and required stimulation. She was subsequently admitted to hospital the next day with diabetic ketoacidosis, so it is unclear whether the apnoea was related to co-morbid illness or immunisation. No serious sequelae were noted. Amongst the seven infants who suffered a second apnoea, five were admitted for supervised administration of their 6-month immunisations. None of the seven infants suffered a further recurrence of apnoea. Exploring potential risk factors for recurrent apnoea following immunisation amongst preterm infants, we found that lower birth weight (p = 0.04) and ongoing hospitalisation for complications relating to prematurity (p = 0.01) increased the odds of a recurrent apnoea AEFI. We found little evidence that requirement for mechanical ventilation or gestational age was associated with recurrent apnoea AEFI. Of the 38 preterm infants with reported apnoea as an AEFI, 33 were over 12 months of age at the time the data were analysed and could therefore be assessed as to whether their immunizations were up to date. Records indicated that 30 (91%) had completed their scheduled immunisations up to and including the 12-month vaccines. Conclusion: There is a risk of recurrence of apnoea associated with immunisation in preterm infants. We recommend that preterm infants with apnoea post immunisation should receive reliable cardiorespiratory monitoring for a minimum of 24 h following the next scheduled immunization. Upon internal review, the first episode of frequent brief apnoea +/- bradycardias for 24h was determined to be an other important medical event. Additional information has been requested.