Bromhexine Hydrochloride Prophylaxis of COVID-19 for Medical Personnel: A Randomized Open-Label Study

Background: Bromhexine hydrochloride has been suggested as a TMPRSS2 protease blocker that precludes the penetration of the SARS-CoV-2 into cells. We aimed to assess the preventive potential of regular bromhexine hydrochloride intake for COVID-19 risk reduction in medical staff actively involved in the evaluation and treatment of patients with confirmed or suspected SARS-CoV-2 infection. Methods: In a single-center randomized open-label study medical staff managing patients with suspected and confirmed COVID-19 were enrolled and followed-up for 8 weeks. The study began at the initiation of COVID-19 management in the clinic. We enrolled 50 participants without a history of SARS-CoV-2 infection: 25 were assigned to bromhexine hydrochloride treatment (8 mg 3 times per day), and 25 were controls. The composite primary endpoint was a positive nasopharyngeal swab polymerase chain reaction (PCR) test to SARS-CoV-2 or the signs of clinical infection within 28 days and at week 8. Secondary endpoints included the symptomatic infection rate and positive nasopharyngeal swab (PCR) tests. Results: The rate of the combined primary endpoint did not differ significantly between the active treatment group (2/25 [8%]) and control group (7/25 [28%]); P = 0.07. A fewer number of participants developed symptomatic infection (confirmed COVID-19) in the treatment group compared to controls (0/25 vs 5/25; P = 0.02). Conclusion: Bromhexine hydrochloride prophylaxis was associated with a reduced rate of symptomatic COVID-19. However, the prophylactic treatment was not associated with a lower combined primary endpoint rate, a positive swab PCR test and/or COVID-19. (ClinicalTrials.gov number, NCT04405999)