The effect of Nigella sativa and vitamin D3 supplementation on the clinical outcome in COVID-19 patients: A randomized controlled clinical trial

Abstract

<b>Background:</b> The coronavirus disease 2019 (COVID-19) is a novel coronavirus that causes severe infection in the respiratory system. Since the immune status plays an essential role in combating COVID-19, herbal medicines, which have an immunomodulatory effect, may help prevent and even treat COVID-19. <i>Nigella</i> <i>sativa</i> is one of the herbal medicines with antiviral and immunomodulatory activities, and its therapeutic effectiveness makes it a promising add-on therapy for COVID-19. In addition, vitamin D3 has an immunomodulatory role, but the effect of therapeutic vitamin D3 supplementation in SARS-CoV-2 infection is still not well-known. <b>Objective:</b> This study aims to investigate the effects of <i>Nigella sativa</i> and vitamin D3 as single supplemental therapies and in combination on viral clearance indicated by a negative polymerase chain reaction and the alleviation of symptoms during the study follow-up duration of 14 days. <b>Patients and Methods:</b> The study design was an open-label randomized controlled clinical trial conducted at the Respiratory Hospital at the Kobry El Qobba Armed Forces Medical Complex. In total, 120 COVID-19 patients with mild to moderate symptoms were randomly assigned to four groups, with thirty patients each, as follows: Group 1 received an oral dose of 900 mg <i>Nigella sativa</i> through 450 mg soft gelatin capsules twice daily for two weeks; Group 2 received 2,000 IU of vitamin D3 through 1000-IU tablets given as two tablets, once daily; Group 3 received 900 mg of <i>Nigella sativa</i> and 2,000 IU of vitamin D3 in the same manner of dosing as in the previous groups; and Group 4 was the control group. All groups received standard therapy for COVID-19 infections and clinical management of COVID-19's clinical symptoms. <b>Results:</b> The <i>Nigella sativa</i>-vitamin D3 combination in addition to the standard therapy for COVID-19 infections significantly contributed to the alleviation of most COVID-19 symptoms: 50% of patients were free of cough after 7 days, 70% showed an absence of fatigue after 4 days, 80% had no headache after 5 days, 90% were free of rhinorrhea after 7 days, and 86.7% of the patients had no dyspnea after 7 days. Moreover, patients in the four studied groups showed a reduced median temperature after 3 days of treatment. Negative results of the polymerase chain reaction (PCR) test recorded on the 7th and 14th day of therapy were superior in the <i>Nigella sativa</i> and vitamin D3 combination arm compared to those of the other studied arms where the value of the odds ratio (OR) on the 7th day was 0.13 with 95% CI: 0.03-0.45 and that of the 14th day was 0.09 with 95% CI: 0.02-0.3. <b>Conclusion:</b> The results of this study showed a promising therapeutic benefit of the administration of <i>Nigella sativa</i> and vitamin D3 combination in COVID-19 patients with mild to moderate symptoms. Additionally, the remarkable viral clearance in a short time interval and reduction in the severity and progression of symptoms recommended the use of this combination as an add-on therapy for the management of COVID-19 patients. <b>Clinical Trial Registration:</b> ClinicalTrials.gov, Identifier: NCT04981743.