Efficacy of over-the-counter immunostimulants in the prevention of paediatric recurrent acute respiratory tract infections. Criticisms and pitfalls of available metanalyses.

UNLABELLED Preschool children frequently suffer from acute respiratory tract infections (ARTI). Immunostimulants (ISs) are often administered to reduce their impact. This study aimed to establish the efficacy of ISs in the prevention of pediatric ARTI through the analysis of systematic reviews (SRs). We explored Medline database in October 2010 limiting our search to SRs, that included studies on the effectiveness of ISs in the prevention of pediatric ARTI. Six SRs with meta analysis (MA) were found. The studies included showed a low methodological quality and a high statistical heterogeneity. All papers published on journals with impact factor > 1 and a Jadad score > 3 reviewed the efficacy of OM-85. The number needed to treat (NNT) was between 2 and 11, depending on the setting. CONCLUSIONS Pediatric ARTI are a social and health care problem. When they impair the quality of life of the family a course of OM-85 might be warranted. Although scientific knowledge of clinicians may be improved by SRs, MA and aggregation of results may not always be the best way to accomplish this.