This is an open-label, controlled, single-centre pilot study of nivolumab in adult patients with COVID-19. This clinical study aims to evaluate efficacy of anti-PD1 antibody in relation to viral clearance and its safety.

Inclusion Criteria:

• Diagnosis of COVID-19 by RT-PCR for SARS-CoV-2
• Clinically stable with disease severity defined as mild or moderate (mild disease is defined as symptoms with or without lung infiltrates on chest X-Ray or CT imaging; moderate disease is defined as lung infiltrates with evidence of type 1 respiratory failure)
• Asymptomatic patients may be enrolled if patients have obvious radiographic changes on chest or CT radiography deemed to be related to COVID-19

Exclusion Criteria:

• Active cancer, rheumatological and autoimmune conditions
• Transplant recipients, or patients on active immunosuppressants
• Chronic organ impairment, or documented or suspected concomitant infections (including chronic viral hepatitis B and hepatitis C) other than SARS-CoV-2
• Lactating mothers and women who are pregnant or intending to become pregnant
• Acute respiratory distress syndrome, evidence of myocardial injury, disseminated intravascular coagulopathy, organ failure, hemophagocytosis, shock, respiratory distress, or need for mechanical ventilation, AICU admission, or high flow oxygen therapy