The aim this study is to investigate the safety and efficacy of Nigella Sativa versus Vitamin D3 versus Nigella Sativa / vitamin D3 combination as supplement for management of COVID-19 .

Corona-virus disease-19 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2, and this virus was first originated from Wuhan city of Hubei province of China spreading around the globe. The prominent symptoms of COVID-19 include fever, cough, dyspnea, and other symptoms noted in patients affected by COVID-19 that includes; chills, repeated shaking with chills, muscle pain, headache, sore throat, and new loss of taste or smell. In addition, the emergency warning signs of COVID-19 include difficulty breathing or shortness of breath, persistent pain or pressure in the chest, new confusion or inability to arouse and bluish lips or face and the patients experiencing any of these signs should get immediate medical attention.

Herbal medicines are used by many people to try to improve their health upon the believe that "natural products" are always safe, and good for immunity based on the traditional knowledge .There is a potential of Nigella Sativa to treat the patients with COVID-19.

Nigella Sativa (NS), a widely used medicinal plant of the family Ranunculaceae ; commonly known as Black Cumin, has been shown to exert antiviral effects against a variety of viruses such as Mouse Cytomegalovirus and Hepatitis C Virus (HCV) . The components' antimicrobial properties against various microbes as well as their anti-inflammatory and immuno-modulatory effects have also been established .

The immune system defends the body from foreign, invading organisms, promoting protective immunity, while maintaining tolerance to self. The implications of vitamin deficiency on the immune system have become clearer in recent years, and in the context of vitamin D deficiency, the increased susceptibility to infection observed, especially in a genetically susceptible host to autoimmunity.

The classical actions of vitamin D are to promote calcium homeostasis, and to promote bone health. In humans, vitamin D is obtained from the diet, or synthesized in the skin as vitamin D is cutaneously produced after exposure to UV light, its synthesis is influenced by latitude, season, use of sun-block and skin pigmentation. Melanin absorbs UV radiation inhibiting the synthesis of vitamin D from 7-dihydrocholesterol. This initial vitamin D compound is inactive form; hydroxylation in the liver to form the active 25 hydroxy vitamin D3 (25 D). Vitamin D is the most reliable measurement of an individual's vitamin D status. It is converted in the kidney to the active compound 1,25 dihydroxy vitamin D (1,25 D) or calcidiol by 1-α-hydroxylase (CYP27B1), an enzyme which is stimulated by parathormone.

A principal defense against uncontrolled inflammation, and against viral infection in general, is provided by T regulatory lymphocytes (Tregs). Treg levels have been reported to be low in many COVID-19 patients, and can be increased by vitamin D supplementation. Low vitamin D levels have been associated with an increase in inflammatory cytokines, and a significantly increased risk of pneumonia, and viral upper respiratory tract infections.

Inclusion Criteria:

1. Patients with mild-moderate COVID-19 according to the classification (Table 1)
2. Adult (18 - 65 years old).
3. Polymerase chain reaction (PCR)-confirmed infection with Severe Acute Respiratory Syndrome Coronavirus-2.

Exclusion Criteria:

1. Patients with severe illness requiring admission to intensive care unit.
2. Asymptomatic patients.
3. Severe chronic kidney disease (i.e. estimated glomerular filtration rate < 30 mL/min) or end stage renal disease requiring dialysis
4. Severe chronic liver disease (Alanine transaminase or Aspartate transaminase > 5 times the upper limit of normal).
5. contraindications to any of the interventional drugs.
6. Pregnancy or breast feeding.
7. Allergy to any of the interventional.