Overview of the characteristics of included studies
| First author [ref]. | Study design | Subjects (BL/control) n | Age | Intervention | Concomitant treatment BL/control µg | Study regimen | Outcome wheezing or asthma episodes in 1 year BL/control | p-value | Outcome immunology BL compared to controls |
| Infant wheezing | |||||||||
| Chen [31] | Open label, prospective study | 43 (24/19) | 6–16 months | OM-85 versus SC | Substitute treatment Standard care consisted of budesonide 200 µg for 3 months | 3 months OM-85/SC 9 months FU | 25% OM-85 group experienced >3 wheezing episodes during follow-up; 63.2% SC group experienced >3 wheezing episodes during follow-up | <0.05 | |
| Razi [36] | Double-blind RCT | 75 (35/40) | 1–6 years | OM-85 versus placebo | Add-on treatment Standard care with ICS 200–800 µg·day−1 Not further specified | 3 months OM-85/placebo 9 months FU | 3.6±1.6/5.8±2.7 | <0.01 | |
| Han [32] | Open label RCT | 136 (74/62) | 7 months to 5 years | OM-85 versus SC | Add-on treatment Standard care: glucocorticoid atomising inhalation, aminophylline and antibiotics | 3 months OM-85/SC 9 months FU | 2.9±0.3/4.5±0.7 | <0.01 | Decrease serum IL-17 Increase serum IFN-γ |
| Sly [33] | Double-blind RCT | 59 (29/30) | 3–9 months | OM-85 versus placebo | No mention of standard care | 6 months OM-85/placebo 6 months SC | 9 episodes (0 (0.0–0.0)), 17 episodes (0 (0.0–1.0)) | 0.04 | |
| Conejero [37] | Double-blind RCT | 120 (62/58) | 6–35 months | MV130 versus placebo | Add-on treatment Standard care according to GINA guidelines | 6 months MV130/placebo 6 months FU | 2.8±1.8/5.3±3.2 | <0.01 | |
| Asthma | |||||||||
| Chen [38] | Open label, prospective study | 45 (29/16) | 5–14 years | OM-85 versus SC | Add-on treatment. Standard care with ICS Doses ICS not specified | 3 months OM-85/SC 9 months FU | 1.0±0.9/2.2±1.5 | <0.05 | No decrease serum IL-4 of IgE |
| Liao [34] | Double-blind RCT | 62 | 4.5 years (mean) | OM-85 versus placebo | Add-on treatment. Standard care with ICS Doses ICS not specified | 3 months OM-85/placebo 3 months SC 3 months OM-85/placebo 3 months FU | Decreased number of lower RTIs in asthma patients, exacerbations not described | Increase serum IgG and serum IgA | |
| Lu [35] | Open label RCT | 60 (24/36) | 5–15 years | OM-85 versus SC | Add-on treatment. Standard care with ICS Doses ICS not specified | 3 months OM-85/SC 3 months SC 3 months OM-85/SC 3 months FU | 0.9±0.7/1.8±1.2 | 0.01 | Increase serum IFN-γ/IL-4 ratio |
| Koatz [30] | Open label, prospective before/after study | 28 | 16–65 years | OM-85 versus SC | Add-on treatment. Standard care with ICS Doses ICS not specified | 9 months SC 3 months OM-85 12 months FU | 0.1±0.7/2.1±1.2 | 0.01 | Increase serum and secretory IgA levels |
| Emeryk [29] | Double-blind RCT | 150 (74/76) | 6–16 years | Ismigen versus placebo | Add-on treatment Mean daily ICS dose: 283±107/289±118 | 3 months Ismigen/placebo 9 months FU | 1.1±1.3/1.9±2.0 | 0.01 | |
Data are presented as mean±sd or median (interquartile range), unless otherwise stated. BL: bacterial lysate; SC: standard care; ICS: inhaled corticosteroids; FU: follow-up; RCT: randomised controlled trial; OM-85: Broncho-Vaxom; ICS: inhaled corticosteroid; IL: interleukin; IFN: interferon; Ig: immunoglobulin; RTI: respiratory tract infection; GINA: Global Initiative for Asthma.