Short-term inhibition of SARS-CoV-2 by hydrogen peroxide in persistent nasopharyngeal carriers.

Asymptomatic and convalescent COVID-19 subjects may carry SARS-CoV-2 for months in their upper respiratory ways. Desiring to permanently clean the mucosal surfaces we investigated chemical agents fit to rapidly degrade the virus. Among these, hydrogen peroxide, initially tested by two of us for tolerability, showed both good performance and acceptable side effects (burning sensation for 15 - 20 seconds). We contacted circles of family physicians and the ATS Milano (Territorial Assistance and Prevention Service) and we tested this procedure on eight persistent carriers of SARS-CoV-2, performing swabs before the procedure and after it until reappearance of the virus or until 14 days (the incubation period), keeping the surfaces clean with hypertonic solution. Our patients had a median time from exposure or symptom onset of 111 days and three had relapsed after being declared 'cured' (two consecutive negative swabs after quarantine). One patient had a baseline negative swab and was excluded, two successfully ended the 14 days' course, four suppressed viral elimination for 72 hours and one for 48 hours, all rebounding to weak positive (cycle thresholds above 24). Although temporarily effective, such measure may have some place in the control of viral shedding, in order to protect the most fragile subjects. This article is protected by copyright. All rights reserved.