Is high dose Vitamin D supplementation effective and safe in the treatment of patients with symptomatic SARS CoV-2 infection and what are the effects and associations of low vitamin D levels in this patient group?

1. Study setting is COVID-19 treatment unit at Base Hospital-Homagama.

2. Simple randomization will be performed using computer generated random sequence allocation. Pre-defined group assignment for each participant (based on enrollment number) will be kept in individual envelopes. This will be done by one of the investigators who will not directly involve in recruitment and outcome assessment. Research assistant will select the pack given to the allocation number and provide it to the in-charge nursing officer of the unit to dispense daily.

3. Intervention: Oral vitamin D 60000international units (chewable) daily for 5 days from date of recruitment followed by 2000 international units (non chewable) daily until time of discharge.

4. Standard treatment that is required for the management of the patient will be continued according to the “Provisional Clinical Practice Guidelines on COVID-19 suspected and confirmed patients” issued by the Ministry of Health Sri Lanka in collaboration with Ceylon College of Physicians in March 2020

Control group participants will receive 60000 international units chewable placebo tablet for 5 days followed by 2000 international units non chewable placebo daily until the time of discharge. 60000 international units chewable placebo tablet contains lactose, maize starch, aspartame, magnesium stearate and talc. It is a white round tablet measuring 10mm × 3.2 mm and tastes sweet. 2000 international units non chewable placebo tablet contains sodium starch glycolate, mycrocrystalline cellulose, calcium hydrogen phosphate, magnesium stearate, opadry. It is a white round tablet measuring 7mm × 3mm and it is coated tablet with no defined taste.

1. Research assistant will select the pack given to the allocation number and provide it to the in-charge nursing officer of the unit to dispense daily

2. Patient, research assistant and the clinician who is in-charge of the patient care will be blind to the agent (drug/ placebo) provided.

• Male or female patients

• Aged over 18 years

• Having mild or moderate illness according to the National Institute of Health Classification system for SARS CoV -2

o Mild illness: Individuals who have any of the various signs and symptoms of COVID-19 (e.g., fever, cough, sore throat, malaise, headache, muscle pain, nausea, vomiting, diarrhea, loss of taste and smell) but who do not have shortness of breath, dyspnea, or abnormal chest imaging.

o Moderate illness: Individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (SpO2) greater than or equal to 94% on room air at sea level.

• Laboratory confirmed SARS-CoV-2 symptomatic infection

• Availability of the patient for recruitment into the study within 96 hours of symptom onset

• Normal corrected/ ionized calcium at the time of admission according to the reference range provided by the laboratory

• Pregnant and/or lactating women
• Prior diagnosis of vitamin D deficiency (less than 20 ng/mL)
• Being on vitamin D supplementation greater than 1000 IU/day within past 3 months:
• Organ failure/ need for ICU stay/ organ support at the time of enrollment
• Patients with any disorder related to calcium metabolism that in the opinion of the investigator does not justify a high dose of vitamin D
• Patients who have been already enrolled in any other clinical trial