Ivermectin Versus Standard Treatment in Mild COVID-19: a Prospective Cohort Study.

1. Introduction and rationale: An outbreak of atypical pneumonia of unknown cause erupted in Wuhan, China in December 2019. The symptoms ranged from mild symptoms to severe acute respiratory distress syndrome, with multi-organ affection leading to patients' death. Within few weeks, genetic sequence of the causative virus was identified to be close to Severe Acute Respiratory Distress Virus (SARS-CoV) (Zhou et al, 2020). The newly identified virus was named Novel Coronavirus or SARS-CoV2, and the clinical disease as COVID-19 (Chung et al, 2021). The disease spread rapidly with travel movements around the world and the World Health organization announced the COVID-19 as a pandemic on March 11th, 2020 (Cucinotta and Vanelli, 2020). The worldwide disease toll approached more the 165 million confirmed cases including more than 3.5 million deaths as of May 21st, 2021, making it the worst pandemic in the last 100 years [WHO Coronavirus (COVID-19) Dashboard].

Attempting to find therapeutic options for COVID-19, viral inhibitor drugs that have been used against influenza and HIV, were repurposed to be tested against SARS-CoV2. These include Chloroquine/ Hydroxychloroquine which inhibit viral entry and endocytosis in vitro, protease inhibitors Lopinavir-Ritonavir which disrupt viral replication in-vitro, and RNA dependent polymerase inhibitors including Ribavirin, Favipiravir and Remdesivir (Wiersinga et al, 2020). Only Remdesivir showed initial promising results in a randomized clinical trial (Beigel et al, 2020), however, currently the World Health Organization recommends against its use in any disease severity (Lamontage et al, 2021).

Ivermectin is an inexpensive and available antiparasitic drug, with favourable safety profile. It showed inhibitory effect on SARS-CoV2 viral replication in vitro and in animal models (Formiga et al, 2021). Several research groups investigated Ivermectin in COVID-19, particularly early in mild disease where viral replication is more active (Kory et al, 2021). In its living guideline on drugs used to treat COVID-19, the WHO recommended against the use of Ivermectin in COVID-19, regardless of duration of symptoms or disease severity, except in the contest of clinical trials. The reason was high degree of uncertainty about clinical outcomes of importance to the patients like time to clinical improvement, hospital admission, duration of hospitalization, mechanical ventilation and mortality. The WHO recommends larger and well-designed studies to solve this uncertainty (Lamontage et al, 2021).

In the present study protocol, the investigators plan to study the effect of Ivermectin versus standard treatment in patients with confirmed mild symptomatic COVID-19. The primary outcome will be rate of intensive care admission. Secondary outcomes will be time to clinical improvement, patient's clinical state using 7-point ordinal scale at different time points, proportion of subjects needing hospitalization, supplemental oxygen >24 hours, duration of hospitalization, duration of ICU stay or death within 21 days.