The newly emerged corona virus disease 2019 (COVID-19) has spread to all over the world, with recent estimates of more than 236 million cases diagnosed and led to 4.8 million deaths as November 20211 .Therapeutic approaches are needed to improve outcomes in patients with COVID-19 since no antiviral agent has yet been proved to be conclusively beneficial in COVID-19 infection,especially in patients with mild to moderate degree of severity There has been growing interest in the anti-parasitic drug,ivermectin, which previously was studied as an antiviral, anti-inflammatory and anti-cancer actions2 .It was also reported to have an in-vitro activity against SARS-CoV-23 .Its antiviral properties was due to the action on importin 2/1 mediated nuclear transport. Ivermectin prevents the binding of viral proteins to importin 2/1 rendering the viral proteins unable to enter the nucleus and cause infection4.

Several clinical studies have found a beneficial effect of ivermectin in COVID-195-9 However, some study did not find significant difference between the patient group receiving ivermectin and control group10 .Until now, the controlled trials evaluating ivermectin in COVID-19 are lacking. Ivermectin is safe, with reported side effect of less than 1%. Hence it is essential to conduct a clinical trial with ivermectin in patients with COVID-19 .The objective of this study is to establish the efficacy of ivermectin for COVID-19 patients with mild to moderate disease, compare to usual case alone.

This study is a randomized, double-blind, placebo controlled trial conducted at Faculty of Medicine, Vajira Hospital, Navamindradhiraj University from September 2021 to the end of November 2021.

The patients were randomized in permuted block of four in a randomized sequence prepared by the unblinded pharmacist in Microsoft excel12 .Allocation assignment was concealed from investigators and the patients. The patients were allocated into two groups : either to group A (Ivermectin arm) or to group B (control arm) as shown in Fig 1. The patients were randomized in a 1:1 ratio .Group A received ivermectin 12 mg per day for 5 days as recommended by previous studes13,14 plus standard care. Group B was to receive standard care alone which included favipiravir or andrographolide, corticosteroids, cetrizine and paracetamol.

Inclusion Criteria:

• adult men and women age 18-80 years
• non-pregnant or breast-feeding women
• had mild to moderate symptoms as defined by the World Health Organization (WHO) severity score for COVID-19 Mild disease was defined as cough , runny nose,anosmia, fever, diarrhea without dyspnea or tachypnea.

Moderate disease was defined as pneumonia but with oxygen saturation more than 90 percent

Exclusion Criteria:

• were allergic to ivermectin
• have the potential for a drug-drug interaction with ivermectin such as tamoxifen or warfarin
• previously treated with ivermectin in the last 7 days
• had received any herbal medicine
• had severe chronic illness (severe congestive heart failure, chronic kidney disease stage 4-5, chronic liver disease, terminal cancer diseases)
• had concurrent bacterial infection or unwilling to participate in the trial
• Patients with severe symptoms, likely due to cytokine release syndrome
• uncontrolled co-morbidities and immunocompromised states

Data will be made available upon request after publication

After publication

Group A: Ivermectin Group B: Placebo