Inclusion Criteria:  Age 18 years or above; Signed informed consent; PCR-confirmed diagnosis of SARS-CoV-2 infection Presenting with moderate-to-severe disease (scores 4-6 on WHO ordinal scale)  Exclusion Criteria:  Women of childbearing age without a negative urine pregnancy test, currently pregnant or breastfeeding women; Severe heart failure (NYHA4), severe renal failure (eGFR < 30 ml/min/1.73 m2), severe liver failure (ALT/AST ratio > 5 norms), severe anemia (haemoglobin < 30 g/l) Participating in another clinical trial Severe electrolyte imbalance (hyperkalemia > 5.0 mmol/l, hyponatremia < 120 mmol/l) Hypersensitivity or contraindications to the study drugs (spironolactone and dexamethasone) Renal dialysis Severe uncontrolled diabetes mellitus Patient receiving one of the following medications that cannot be substituted over the trial duration: ACE inhibitors, amiloride, eplerenone, cortisone acetate, potassium canrenoate, triamterene