Complementary and alternative medicine (CAM) interventions for COVID-19: An overview of systematic reviews.

Background: Since the beginning of the Coronavirus disease 2019 (COVID-19) pandemic, various complementary and alternative medicines (CAMs) have been used in clinical practice. In this overview, we summarized the evidence for CAM interventions in the treatment of COVID-19 patients.

Methods: For this overview, PubMed, Embase and Cochrane Library were searched from inception to October 2021. Systematic reviews (SRs) on the effectiveness and safety of CAM interventions for COVID-19 patients were located, and the MeaSurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) was used to evaluate the reporting quality of the included SRs. Keywords including COVID-19 and CAM interventions were used for locating SRs. For evidence mapping, we created a two-dimensional bubble plot that included the width and strength of the evidence for each CAM intervention and specific outcome.

Results: In this overview, we identified 24 SRs (21 for Traditional Chinese Medicine (TCM) medications, two for vitamin D and one for home-based activity). From the included SRs, TCM herbal medications were reported to show good results in decreasing the rate of disease progression (relative risk (RR) 0.30, 95% confidence intervals (CI) [0.20, 0.44]), time to the resolution of fever (standard mean difference (SMD) -0.98, 95% CI [-1.78, -0.17]) and rate of progression to severe COVID-19 cases (RR 0.34, 95% CI [0.18, 0.65]), but the evidence for other interventions did not show effectiveness with certainty. Gastric disturbance was a major adverse event of TCM medications.

Conclusion: There is evidence that TCM medications are effective in the symptom management of COVID-19 patients. However, evidence for the effectiveness of most CAM interventions still needs evaluation.