Bacterial immunotherapy is highly effective in reducing recurrent upper respiratory tract infections in children: a prospective observational study

PURPOSE: Whilst immunotherapy is an appealing option as it could reduce the burden of recurrent pediatric respiratory tract infections (RTI), there is limited evidence on its effectiveness and more research was requested in order to better understand this therapeutic modality. METHODS: We performed a prospective cohort study involving 57 subjects to assess the safety and effectiveness a 3-month regimen of either typified or patient-specific bacterial lysates could have in reducing the number of RTIs in children aged 0 to 11 years with histories of recurrent episodes. RESULTS: After a 6-month follow-up, the number of RTIs and school absenteeism dropped sharply and significantly, from an adjusted mean (standard error) of 0.6 (0.04) episodes/month to 0.1 (0.03) episodes/month (74.7% reduction, P < 0.001), and from an adjusted mean score of 4.6 (1.06) points to 0.0 (0.01) points over 10 (99.5% reduction, P < 0.001), respectively. There was also a significant decrease in the severity of symptoms. No adverse reactions were observed. CONCLUSION: The use of the study product is associated with a decreased risk of recurrent RTIs in children, with a very favorable safety profile that warrants further investigation in randomized clinical trials. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00405-023-08035-4.