title: Frequency of respiratory deterioration after immunisation in preterm infants.
abstract: OBJECTIVE
  To determine the relationship between the initiation of respiratory support and the first routine immunisation of neonates at 2 months of age during primary hospitalisation.
  
  
  METHODS
  An historical cohort study design was used to study the neonatal factors associated with the initiation of respiratory support within 7 days of immunisation in a cohort of 7629 preterm and term infants admitted to the Neonatal Unit of the Royal Women's Hospital between 2001 and 2008.
  
  
  RESULTS
  The 411 infants who received their first immunisations in hospital were both very preterm and of extremely low birth weight (ELBW, below 1000 g). Twenty-two infants experienced post-immunisation apnoea of sufficient severity to warrant the initiation of either intermittent positive pressure ventilation (two cases) or continuous positive airway pressure (20 cases). Infants exhibiting a respiratory deterioration following immunisation had a higher incidence of previous septicaemia (Odds ratio 2.5, 95% confidence interval 1.0, 6.1; P = 0.04) and received CPAP for a longer period prior to vaccination (P = 0.03).
  
  
  CONCLUSIONS
  Apnoea following immunisation may be an aetiological factor in the requirement of respiratory support in a small number of preterm, ELBW infants particularly those with significant lung disease and those who have previously experienced septicaemia.
authors.affiliation: Division of Newborn Services, The Royal Women's Hospital, 20 Flemington Road, Parkville, Vic. 3052, Australia. doug.hacking@thewomens.org.au
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Hacking
authors.forename: Peter G
authors.initials: PG
authors.lastname: Davis
authors.forename: Ester
authors.initials: E
authors.lastname: Wong
authors.forename: Kevin
authors.initials: K
authors.lastname: Wheeler
authors.forename: Jodie
authors.initials: J
authors.lastname: McVernon
mesh_terms: D015331:Cohort Studies; D006801:Humans; D007114:Immunization / Q000009:adverse effects*; D007223:Infant; D007231:Infant, Newborn; D017063:Outcome Assessment, Health Care; D047928:Premature Birth; D012131:Respiratory Insufficiency / Q000139:chemically induced / Q000453:epidemiology*; D014739:Victoria / Q000453:epidemiology