COVID-19: discovery, diagnostics and drug development

Asselah, Tarik; Durantel, David; Pasmant, Eric; Lau, George; Schinazi, Raymond F.

An epidemic of acute respiratory syndrome (Covid-19) started in humans in Wuhan in 2019, and became a pandemic. Groups from China Identified and sequenced the virus responsible for COVID-19, named SARS-CoV-2, and determined that it was a novel coronavirus (CoV) that shared high sequence identity with bat- and pangolin-derived SARS-like CoVs, suggesting a zoonotic origin. SARS-CoV-2 is a member of Coronaviridae, a family of enveloped, positive-sense, single-stranded RNA viruses that infect a broad range of vertebrates. The rapid release of the sequence of the virus has allowed the development of diagnostic tools (e.g., RT-PCR). Additionally, serological tests can allow identification of persons who have been infected. In humans, CoVs tend to cause mild to moderate upper respiratory tract infections. The fatality rate is around 1-3% for infected persons. An acute respiratory distress syndrome (ARDS) likely due to an uncontrolled immune activation (“cytokine storm”) occurs in patients with severe disease and poor prognosis. Risk factors for mortality include: advanced age, obesity, diabetes, hypertension and other comorbidities. Drug repurposing has been used to rapidly identify potential treatment for COVID-19, which could move quickly to phase-3. Better knowledge of the virus, its enzymes, will be mandatory to develop more potent and specific direct-acting antiviral agents (DAA). In the long term, a vaccine to prevent infection would be crucial; however even if successful it might not be available before 2021-22. To date, with the exception of intravenous Remdesivir and dexamethasone, which have modest effects in moderate to severe COVID-19, no strong clinical evidence supports the efficacy and safety of any other drugs against SARS-CoV-2. The aim of this review is to provide insights on the discovery of SARS-CoV-2, its virology, the diagnostic tools, and the ongoing drug discovery effort.