Catalysing the Containment of COVID-19

COVID-19 due to SARS-CoV-2 infection is a rapidly escalating global pandemic for which there is no proven effective treatment. COVID-19 is multi-dimensional disease caused by viral cytopathic effects and host-mediated immunopathology. Therapeutic approaches should logically be based on interventions that have direct anti-viral effects and favourably modulate the host immune response. Thus, an optimal drug regimen in ambulatory patients should collectively (i) target and reduce viral replication, (ii) upregulate host innate immune anti-viral responses, (iii) have favourable immunomodulatory properties, and (iv) minimise disease progression to hospitalisation thus circumventing the 'cytokine storm' that likely underpins ARDS and multi-organ failure. Nitazoxanide (NTZ) is an antiprotozoal drug that is FDA-approved for treating Cryptosporidium and Giardia and has an excellent safety record for a variety of indications, but primarily as an anti-parasitic agent. It has proven broad anti-viral activity as it amplifies cytoplasmic RNA sensing, potently augments type I interferon and autophagy-mediated anti-viral responses, has immunomodulatory properties e.g inhibits macrophage IL-6 production, and interferes with SARS-CoV-2 glycosylation. It has been shown to have anti-viral activity against several viruses including Ebola, influenza, hepatitis B and C, rotavirus and norovirus. With regard to respiratory viral infections, NTZ was evaluated in uncomplicated influenza and demonstrated a reduction in the median time to symptom recovery. By contrast, NTZ failed to show benefit in hospitalised patients with severe influenza suggesting that, as with oseltamivir (Tamiflu), it likely needs to be administered early in the course of the disease. NTZ has proven in vitro activity against SARS-CoV-2. NTZ inhibited the SARS-CoV-2 at a low-micromolar concentrations and in vivo evaluation in patients with COVID-19 has been strongly recommended. NTZ has an excellent drug-drug interaction