title: Oral purified bacterial extracts in acute respiratory tract infections in childhood: a systematic quantitative review.
abstract: BACKGROUND
  Recurrent acute respiratory tract infections (ARTI) are a common problem in childhood. Some evidence suggests a benefit regarding the prevention of ARTI in children treated with the immunomodulator OM-85 BV (Bronchovaxom).
  
  
  METHODS
  We summarised the evidence on the effectiveness of the immunomodulator OM-85 BV in the prevention of ARTI in children. We searched randomised comparisons of oral purified bacterial extracts against inactive controls in children with respiratory tract diseases in nine electronic databases and reference lists of included studies. We extracted salient features of each study, calculated relative risks (RR) or weighted mean differences (WMD) and performed meta-analyses using random-effects models.
  
  
  RESULTS
  Thirteen studies (2,721 patients) of low to moderate quality tested OM-85 BV. Patients and outcomes differed substantially, which impeded pooling results of more than two trials. Two studies (240 patients) reporting on the number of patients with less than three infections over 6 month of follow-up in children not in day care showed a trend for benefit RR 0.82 (95% CI, 0.65-1.02). One out of two studies examining the number of children not in day care without infections over 4-6 month reported a significant RR of 0.42 (95% CI, 0.21-0.82) whereas the smaller, second study did not [RR 0.92 (95% CI, 0.58-1.46)]. Two studies reporting the number of antibiotic courses indicated a benefit for the intervention arm [WMD 2.0 (95% CI, 1.7-2.3)]. Two out of the three studies showed a reduction of length of episodes of 4-6 days whereas a third study showed no difference between the two groups.
  
  
  CONCLUSIONS
  Evidence in favour of OM-85 BV in the prevention of ARTI in children is weak. There is a trend for fewer and shorter infections and a reduction of antibiotic use.
authors.affiliation: Medical Policlinic, Department of Internal Medicine, University Hospital, Raemistrasse 100, CH-8091, Zurich, Switzerland. claudia.stey@usz.ch
authors.forename: Claudia
authors.initials: C
authors.lastname: Steurer-Stey
authors.forename: Leonie
authors.initials: L
authors.lastname: Lagler
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Straub
authors.forename: Johann
authors.initials: J
authors.lastname: Steurer
authors.forename: Lucas M
authors.initials: LM
authors.lastname: Bachmann
mesh_terms: D002648:Child; D006801:Humans; D000208:Acute Disease; D000276:Adjuvants, Immunologic / Q000627:therapeutic use; D001419:Bacteria; D012141:Respiratory Tract Infections / Q000517:prevention & control; D055502:Secondary Prevention; D000095983:Bacterial Lysates
chemical_list: D000276:Adjuvants, Immunologic; C030259:Broncho-Vaxom; D000095983:Bacterial Lysates