Nasal-spraying Bacillus spores as an effective symptomatic treatment for children with acute respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is a leading cause of Acute Respiratory Tract Infections (ARTIs) in young children. However, there is currently no vaccine or treatment available for children. Here, we demonstrated that nasal-spraying probiotics containing 5 billion of Bacillus spores (LiveSpo Navax) is an effective symptomatic treatment in a 6-day randomized controlled clinical study for RSV-infected children ( n = 40–46/group). Navax treatment resulted in 1-day faster recovery-time and 10–50% better efficacy in relieving ARTI symptoms. At day 3, RSV load and level of pro-inflammatory cytokines in nasopharyngeal samples was reduced by 630 folds and 2.7–12.7 folds respectively. This showed 53-fold and 1.8–3.6-fold more effective than those in the control-standard of care-group. In summary, nasal-spraying Bacillus spores can rapidly and effectively relieve symptoms of RSV-induced ARTIs while exhibit strong impacts in reducing viral load and inflammation. Our nasal-spraying probiotics may provide a basis for simple-to-use, low-cost, and effective treatment against viral infection in general.