Nigella sativa for the treatment of COVID-19 patients: A rapid systematic review and meta-analysis of randomized controlled trials

Nigella sativa is an herbal therapy for various afflictions. It has some potential to be a promising option as an efficacious treatment for COVID-19 patients that can contribute to global healthcare as a relatively cheap therapy but evidence of its use from randomized controlled trials (RCTs) is limited. Therefore, to explore the effect of N. sativa in combating COVID-19, we undertook this meta-analysis. We searched several databases to retrieve all RCTs investigating N. sativa for the treatment of COVID-19 as compared to placebo or standard care. We used RevMan 5.4 for all analyses with risk ratio (RR) or odds ratio (OR) as the effect measures. We included a total of seven RCTs in this review. N. sativa significantly reduced the risk of all-cause mortality in patients with COVID-19 compared to the control group (RR 0.27, 95% CI: 0.10 to 0.72; I-2 = 0%). N. sativa significantly reduced the rate of viral PCR positivity (RR 0.62, 95% CI: 0.39 to 0.97; I-2 = 0%). We did not find any significant difference in the risk of hospitalization (RR 0.26, 95% CI: 0.04 to 1.54; I-2 = 0%) and the rate of no recovery (OR 0.48, 95% CI: 0.20 to 1.15; I-2 = 84%) between the two groups. N. sativa is an easily available herbal medicine that may decrease the risk of mortality and improve virological clearance in COVID-19 patients. However, our results are limited by the small number of RCTs available. Further large-scale RCTs are needed to better understand the anti-inflammatory and antiviral effects of N. sativa in COVID-19 patients.