Inclusion Criteria:  Male or female aged ≥ 40 years; Symptomatic adults with confirmed COVID-19 (SARS-COV-2 PCR positive) for at least 24 hrs. and no more than 7 days: by report or observation, including one or more of the following: temperature ≥ 38°C (≥100.4°F), chills or shivering, cough, difficulty breathing, fatigue, headache, muscle or body ache, anosmia (loss of smell) and/or dysgeusia (loss of taste), GI symptoms (nausea and/or vomiting);  (3a) Aged ≥70 years or above, presence of concomitant comorbidity not required for inclusion  or  (3b) Aged ≥40 to <70 years, and presence of at least one of the following concomitant comorbidities by report, history, or observation:  Cardiovascular diseases (e.g., hypertension, coronary artery diseases, congestive heart failure, symptomatic arrhythmia, transient brain ischemia, stroke) Chronic respiratory diseases (e.g., Chronic Obstructive Pulmonary Disease (COPD), asthma, pulmonary fibrosis) Obesity (BMI >30 kg/m^2) Type 2 Diabetes Cancer (participant reported: stable >6 months as per treating doctor/oncologist)  Autoimmune diseases (T1D, RA, PA, MS, IBD, AD, SS, HT, SLE)  (4) Participant is considered suitable for continued management in the out-patient setting.  (5) Non-pregnant non-breastfeeding women of reproductive age group not planning pregnancy and/or adopting advised contraception during the study and for 3 months after the last dose of study medication.  Exclusion Criteria:  Unable to provide consent; diagnosis of dementia or other significant neurocognitive disorder; Current hospitalization; Patient requiring long term oxygen treatment of > 5 L O2/min because of a chronic lung condition at time of recruitment; Known intolerance/allergy to sulfone; Pregnant or breastfeeding women or is considering becoming pregnant during the study and for 3 months after the last dose of study medication; Concurrent malignancy on systemic chemotherapy or immunotherapy; Significantly impaired renal function within the past year reported by history and estimated glomerular filtration rate (eGFR) < 60 mL/min at screening Severely underweight (≤ 40 kg) G6PD deficiency (previous jaundice, jaundice with foods such as beans, or medication such as sulfa drugs, NSAIDs, quinolones, hydroxychloroquine or vitamin C), significant blood dyscrasia or anemia (Hb <12.0 g/dL in women and <13.0 g/dL in men; platelet count <50 x 10^9/L or < lower limit of normal at screening) Impairment liver function [> 2 times the upper limit of normal (ULN) at screening at screening for AST, ALT, ALP, GGT, albumin or bilirubin), liver cirrhosis or hepatitis Current use of folic acid antagonists (such as pyrimethamine), nitrofurantoin or primaquine Currently taking oral dapsone for dermatological or other indications Currently taking hydroxychloroquine or if have taken it within the last 6 months Currently on any of the following medications: Aminolevulinic acid; Cladribine; Clozapine; Deferiprone; Prilocaine; Saquinavir; Sodium nitrite, Rifampin or St. John's wort Received any of the following vaccines in the last 1 year : Cholera vaccine live; Typhoid vaccine, live; BCG (Bacillus Calmette and Guérin) Currently taking any the following anticonvulsants : carbamazepine, phenytoin, levetiracetam and gabapentin Currently participating in other interventional trials Inability to provide contact details of caregiver/ next of kin to be contacted for study follow-up as participant's surrogate Currently taking trimethoprim