Inclusion Criteria:  Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by at least 1 positive Polymerase Chain Reaction (PCR) test Moderate COVID as evidenced by Oxygen saturation <93% on room air (or <88% if prior CLD) Admission to emergency department for monitoring and/or supportive care: The following biochemical markers: Absolute neutrophil count (ANC) ≥ 1.5 x 109/L. Platelets ≥ 100 x 109/L, Haemoglobin ≥ 9x 109/L. Bilirubin < 1.5 times upper limit of normal (ULN). Alanine aminotransferase (ALT) and Aspartate Aminotransferase (AST) < 2.5 times ULN. Calculated creatinine clearance of ≥ 30ml/min calculated using the formula of Cockcroft and Gault: (140-age) x mass (kg)/)72x creatinine mg/dl); multiple by 0.85 if female.  Laboratory features of cytokine release, as defined by any 1 of the following:  i. C-reactive protein (CRP)> 75mg/L ii. Lactate Dehydrogenase (LDH) > ULN iii. D-dimer > 1.0 mg/L iv. Ferritin > 500ng/ml v. Elevated Interleukin-6 levels  Exclusion Criteria:  Patients requiring mechanical ventilation Any immunosuppressive medication including chemotherapy(excluding steroids) administered concurrently or within last 14 days. Patients with uncontrolled diabetes mellitus (HbA1C within 1 month >8) Pregnancy or Breastfeeding. Known allergy to Topotecan. Unconjugated hyperbilirubinemia on a fasting Liver Function Test (LFT), which can indicate Gilberts Syndrome. Suspected active bacterial, fungal, or other infection in addition to COVID-19. Any condition that would, in the opinion of the Investigator, increase the risk of the participant by participating in the study. Inability to provide consent. Unable to comply with study procedures.