COVID‐19 Prophylactic Effect of Bromhexine Hydrochloride

INTRODUCTION: Despite extensive efforts to identify effective treatments for COVID-19, preventive strategies remain essential. Bromhexine hydrochloride (BRH), an over-the-counter mucolytic with potential TMPRSS2 inhibition, may reduce viral entry and thus serve as a prophylactic agent. METHODS: A retrospective questionnaire-based study included 125 individuals reporting prophylactic BRH use. Demographic and clinical data were collected. COVID-19 infection rates before and after BRH use were compared. Subgroup analyses were performed by vaccination status, prior infection, and duration of prophylaxis. RESULTS: Participants had a mean age of 56.5 years and a mean BMI of 25.6; 20% were vaccinated. Prior to BRH use, 62.4% reported COVID-19 infection, compared to 11.2% after prophylaxis (p < 0.0001). Significant reductions were observed in both vaccinated (48.1% vs. 3.7%, p = 0.002) and unvaccinated individuals (66.3% vs. 13.3%, p < 0.0001). Prior infection did not significantly influence outcomes (p = 0.9248). Longer BRH use was associated with lower reinfection rates, decreasing from 33.3% (≤ 10 days) to 2.6% (≥ 30 days) (p = 0.003). CONCLUSIONS: BRH prophylaxis was associated with reduced reported COVID-19 infection rates, independent of vaccination or prior infection, with greater benefit observed with longer use. Prospective controlled studies are required to confirm these findings.