Background/aim: The aim of this study was to evaluate the safety and efficacy of AFree oral spray, in combination with Standard of Care, in treating mild to moderate COVID-19 patients. This was an open-label, single-blinded, and controlled randomized clinical trial.

Patients and methods: The study involved 1,252 patients, who were randomly assigned to either the control or study group, with 626 patients in each group. Patients in the control group were treated with Standard of Care recommended by the Ministry of Health of Vietnam, while patients in the study group received AFree oral spray in addition to Standard of Care for a period of 10 days. The clinical progression and outcomes of both groups were compared.

Results: The results showed that the proportion of patients with clinical symptoms on the 5^th, 7^th and 10^th days were significantly lower in the study group (45.05%, 3.19% and 0%, respectively) compared to the control group (86.10%, 67.73% and 22.84%, respectively). Additionally, the rate of Real-time PCR test positivity for COVID-19 was significantly lower in the study group compared to the control group on the 4^th, 7^th, and 10^th days (82.75% vs. 98.72%, 9.27% vs. 92.97%, and 1.12% vs. 50.48%, respectively). Furthermore, no side effects or complications related to AFree oral spray were recorded in the study group.

Conclusion: The use of AFree oral spray resulted in significant improvements in clinical symptoms, recovery time, and viral clearance in COVID-19 patients with mild to moderate symptoms. This therapy has been shown to be safe and can be used as an adjuvant treatment for COVID-19 as well as other respiratory viral infections.