Fourteen-days Evolution of COVID-19 Symptoms During the Third Wave in Non-vaccinated Subjects and Effects of Hesperidin Therapy: A randomized, double-blinded, placebo-controlled study.

COVID-19 symptoms can cause substantial disability, yet no therapy can currently reduce their frequency or duration. We conducted a double-blind placebo-controlled trial of hesperidin 1000 mg once-daily for 14 days in 216 symptomatic non-vaccinated COVID-19 subjects. Thirteen symptoms were recorded after 3, 7, 10 and 14 days. The primary endpoint was the proportion of subjects with any of four cardinal (group A) symptoms: fever, cough, shortness of breath or anosmia. At baseline, symptoms in decreasing frequency were: cough (53.2%), weakness (44.9%), headache (42.6%), pain (35.2%), sore throat (28.7%), runny nose (26.9%), chills (22.7%), shortness of breath (22.2%), anosmia (18.5%), fever (16.2%), diarrhea (6.9%), nausea/vomiting (6.5%) and irritability/confusion (3.2%). Group A symptoms in the placebo vs hesperidin group was 88.8% vs 88.5% (day 1) and reduced to 58.5 vs 49.4 % at day 14 (OR 0.69, 95% CI 0.38-1.27, p = 0.23). At day 14, 15 subjects in the placebo group and 28 in the hesperidin group failed to report their symptoms. In an attrition bias analysis imputing "no symptoms" to missing values, the hesperidin group shows reduction of 14.5 % of group A symptoms from 50.9% to 36.4% (OR: 0.55, 0.32-0.96, p = 0.03). Anosmia, the most frequent persisting symptom (29.3%), was lowered by 7.3% at 25.3 % in the hesperidin group vs 32.6% in the placebo group (p = 0.29). Mean number of symptoms in placebo and hesperidin was 5.10 {+/-} 2.26 vs 5.48 {+/-} 2.35 (day 1) and 1.40 {+/-} 1.65 vs 1.38 {+/-} 1.76 (day 14) (p = 0.92). In conclusion, most non-vaccinated COVID-19 infected subjects remain symptomatic after 14 days with anosmia being the most frequently persisting symptom. Hesperidin 1g daily may help reduce group A symptoms. Earlier treatment of longer duration and/or higher dosage should be tested.