Methods: 109 children with ages between 4 to 16 years with frequent respiratory tract infections (2 to 5 infections the previous winter) were evaluated. Participants were randomly allocated in two groups: 52 patients (mean age 6.8 ± 2.9 years; 20 males 32 females) received no preventive therapy (NPT group) and 57 (mean age 9.0 ±3.3 years; males 36 females 21) received immunotherapy with oral bacterial lysates + vitamin C (VC group) at the recommended dosage. Patients were followed up for 6 months, including the administration period. Primary end points were the type and number of ARTIs. Secondary end points (after the infection occured) included: time to clinical cure, severity of infection, absenteeism from school due to an ARTI, number of antibiotic courses or other drugs prescribed, and duration of concomitant drug treatment.
Results: There were significant differences between groups in the cumulative number of acute infectious episodes: 170 in NPT group (141 upper ARTIs, 29 lower ARTI, and 26 otitis episodes) vs 55 in VC group (50 upper ARTIs, 5 lower ARTI and 4 otitis episodes). Patients in the NPT group received 127 antibiotic courses compared to 28 in the VC group (p<0.0001). Patients in the NPT group had 475 days of absenteeism from school compared to 100 days in the VC group (p<0.0001). No adverse events related to the trial medications were reported.
Conclusions: Immunotherapy with oral bacterial lysates and vitamin C appears to be very effective in the prevention of infectious episodes in pediatric patients with frequent respiratory tract infections. Future studies are needed to further explore the role of oral bacteroial lysates in ARTIs prevention.