title: Multiple vaccinations, health, and recall bias within UK armed forces deployed to Iraq: cohort study.
abstract: OBJECTIVE
  To assess the relation between self reported number of vaccinations received and health, and between numbers of vaccinations recorded from individuals' medical records and health.
  
  
  METHODS
  First phase of a cohort study.
  
  
  METHODS
  UK armed forces personnel.
  
  
  METHODS
  4882 randomly selected military personnel deployed to Iraq since 2003 and a subset of 378 whose vaccination records were accessed.
  
  
  METHODS
  Psychological distress, fatigue, symptoms of post-traumatic stress disorder, health perception, and multiple physical symptoms.
  
  
  RESULTS
  Personnel who reported receiving two or more vaccinations on a single day were more likely to report symptoms of fatigue (adjusted risk ratio 1.17, 95% confidence interval 1.05 to 1.30), show caseness according to the general health questionnaire (1.31, 1.13 to 1.53), and have multiple physical symptoms (1.32, 1.08 to 1.60). These associations were no longer significant when number of vaccinations recorded in individuals' medical records was used as the independent variable.
  
  
  CONCLUSIONS
  Multiple vaccinations given to personnel in the UK armed forces in preparation for deployment to Iraq are not associated with adverse health consequences when vaccinations are recorded objectively from medical records. Adverse health consequences associated with self reported multiple vaccinations could be explained by recall bias.
authors.affiliation: King's Centre for Military Health Research, King's College London SE5 9RJ. dominic.murphy@iop.kcl.ac.uk
authors.forename: Dominic
authors.initials: D
authors.lastname: Murphy
authors.forename: Matthew
authors.initials: M
authors.lastname: Hotopf
authors.forename: Simon
authors.initials: S
authors.lastname: Wessely
mesh_terms: D000328:Adult; D015982:Bias; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007493:Iraq; D054542:Iraq War, 2003-2011; D008297:Male; D008603:Mental Health; D011939:Mental Recall; D008889:Military Personnel / Q000523:psychology / Q000706:statistics & numerical data*; D006113:United Kingdom; D014611:Vaccination / Q000523:psychology / Q000706:statistics & numerical data*