Effectiveness of hydrogen peroxide as auxiliary treatment for hospitalized COVID-19 patients in Brazil: preliminary results of a randomized double-blind clinical trial.

OBJECTIVES: To evaluate the effectiveness of hydrogen peroxide (H2O2) in the form of mouthwash and nasal spray as an auxiliary treatment for coronavirus disease 2019 (COVID-19). METHODS: Forty hospitalized patients who tested positive for severe acute respiratory syndrome coronavirus 2 using a reverse-transcription polymerase chain reaction test were evaluated. They were randomly divided into an experimental group (n= 20; gargling with 1.0% H2O2 and nasal wash with 0.5% H2O2) or a control group (n= 20). The solutions were used for 7 days and the patients were monitored every 2 days, for a total of 8 days. At check-ups, patients were asked about their symptoms and possible adverse effects of the solutions. The presence and severity (mild, moderate, or severe) of symptoms were recorded. Data were compared using the Student test and the Fisher exact test (α= 0.05). RESULTS: There was no significant difference between the 2 groups in the length of hospital stay (p= 0.65). The most frequent symptom on day 0 was coughing (72.0% in the experimental group and 76.5% in the control group), which abated over time. There was no significant difference between the groups in the evaluated symptoms. Most (75.0%) of the patients in the experimental group presented a reduction in dyspnea between days 0 and 2. Few patients reported adverse effects from the use of the solutions. CONCLUSIONS: H2O2 as a mouthwash and nasal spray is safe to use. There is insufficient evidence to demonstrate that H2O2 is effective as an auxiliary treatment for hospitalized COVID-19 patients.

Hydrogen peroxide as an auxiliary treatment for COVID-19 in Brazil: a randomized double-blind clinical trial.

OBJECTIVES: This study evaluated the effectiveness of hydrogen peroxide (H2O2) as mouthwash and nasal spray on symptom relief in coronavirus disease 2019 (COVID-19) patients. METHODS: Patients positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), who were treated in a hospital or at home, and patients' family members (not positive for SARS-CoV-2), were randomized into 2 groups: experimental (1% H2O2 for gargling, 0.5% H2O2 for nasal wash), and control. Patients gargled the solution 3 times a day, and applied the nasal spray twice a day, for a 7-day period. Family members received the same treatment as the treated COVID-19 patient. The researchers contacted patients every 2 days over an 8-day period. An average post-treatment interval of 8 days passed before testing family members. RESULTS: The most frequent symptoms on day 0 were cough, loss of taste, and hyposmia; there were no significant differences between groups, independent of the period. The symptom of dyspnea presented a significant difference between days 2 and 4 (p<0.05). Among family members, 86.0% had no antibodies, 2.3% had antibodies, and 11.6% had active infections (4 in the experimental group and 6 in the control group). The most frequent adverse effects in the H2O2 group were a burning throat and nose. CONCLUSIONS: H2O2 was not effective for the relief of COVID-19 symptoms and was associated with reports of transient adverse effects.