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

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.

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.

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.

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.