Pilot survey among patients taking bromhexine prophylactically against influenza.

Background: The successful use of bromhexine hydrochloride (BRH) for COVID-19 prevention led us to apply the same method for flu prevention. The goal of this study is to observe whether BRH could protect people against influenza. Methods: This is noninterventional, observational, questionnaire-based survey. General practitioners informed their patients to take BRH 8 mg twice per day for at least 3 weeks if they want. The mean participant age was 58.9 years (95% CI: 57.4-60.5), with a median of 62 years, indicating that the sample predominantly consisted of individuals over 60 years of age. Results: The average number of comorbidities was 0.98, and the mean duration of prophylactic use was 80 days (95% CI: 76.7-83.7). The reported influenza incidence within the sample was 10.6%. Influenza incidence among individuals taking BRH prophylactically was significantly lower compared to national data (36.15%). Conclusion: Longer use was associated with a modest reduction in risk. The number of comorbidities remained the strongest predictor of influenza occurrence. Age had no significant impact among those using BRH prophylactically. The model demonstrated good discriminative ability but limited calibration, and the results should be interpreted cautiously.