Efficacy of propolis as an adjunct treatment for hospitalized COVID-19 patients: a randomized, controlled clinical trial

Among candidate treatment options for COVID-19, propolis, produced by honey bees from bioactive plant exudates, has shown potential against viral targets and has demonstrated immunoregulatory properties. We conducted a randomized, controlled, open-label, single center trial, with a standardized propolis product (EPP-AF) on hospitalized adult COVID-19 patients. Patients received standard care plus propolis at an oral dose of 400mg/day (n=40) or 800mg/day (n=42) for seven days, or standard care alone (n=42). Standard care included all necessary interventions, as determined by the attending physician. The primary end point was the time to clinical improvement defined as the length of hospital stay or oxygen therapy dependency. Secondary outcomes included acute kidney injury and need for intensive care or vasoactive drugs. Time in the hospital after intervention was significantly shortened in both propolis groups compared to the controls; median 7 days with 400mg/day and 6 days with 800mg/day, versus 12 days for standard care alone. Propolis did not significantly affect the need for oxygen supplementation. With the higher dose, significantly fewer patients developed acute kidney injury than in the controls (2 versus 10 of 42 patients). Propolis as an adjunct treatment was safe and reduced hospitalization time. The registration number for this clinical trial is: NCT04480593 (20/07/2020).