Citation:
Severe lower respiratory illnesses (sLRIs) during infancy (ie, those associated with fever [>38°C], wheeze, or both) increase the likelihood of subsequent asthma in at-risk subjects. Moreover, time to first sLRI after birth appears to be significantly reduced in children with persistent wheeze, suggesting that early infancy might be a period of particularly high vulnerability to the “asthmatogenic” effects of these infections. Significant interest exists in primary prevention of asthma, and we have previously postulated that this might be achievable through protection against sLRIs during infancy. However, progress in testing this hypothesis has been limited by the availability of appropriate therapeutics approved for use in this age group. In this regard the immunomodulator OM-85 (Broncho-Vaxom; Vifor Pharma, St Gallen, Switzerland) has been used in Europe to prevent recurrent upper respiratory tract infections (URIs) in children and to reduce the frequency and severity of wheeze episodes in asthmatic children. OM-85 is a lyophilized extract derived from a mixture of bacterial respiratory pathogens containing multiple Toll-like receptor–like ligands with a long history of safe use in children. However, it has not been tested previously in the specific context of sLRI prevention in at-risk infants. Accordingly, we conducted a randomized clinical trial (BV2012/15, ACTRN12612000518864) in which at-risk infants, by virtue of a parental history of asthma and allergies, were randomized to OM-85 (3.5 mg) or identical placebo for the first 10 days of April through August, 1 month before and during the months of the winter viral seasons in Brisbane, Australia.
Primary prevention of severe lower respiratory illnesses in at-risk infants using the immunomodulator OM-85
The effects of OM-85 were strongest in the first winter season, with a trend for fewer children in the OM-85 group to have sLRIs and URIs