Interim Report on a Live Review of Systematic Reviews of Natural Health Products and Natural Therapies in the Prevention and/or Treatment of COVID-19

Objective: This living review of systematic reviews investigates the types and volume of research pertaining to natural health products and therapies as they relate to the prevention and/or treatment of COVID-19 and post-COVID syndrome. Methods: A monthly search for published peer-reviewed systematic reviews of the topic was initiated May 2022 and is ongoing. Using a systematic keyword search strategy with clear inclusion and exclusion criteria, a summary of the types of studies included, the overall outcome and treatment focus were assessed. Results: A total of 225 systematic reviews encompassing 5,636 studies of randomized controlled trials (49.8%, n=112), observational studies (21.3%, n=48), clinical studies (20.4%, n=46), and other studies (12%, n=27) were included. Of those, 28.9% (n=65) of the systematic reviews focused on prevention, 67.6% (n=152) on treatment, and 3.1% (n=8) on post-COVID. The natural health products reviewed included herbal medicine, vitamins, minerals, other natural health products, and other therapies, with 83.5% (n=188) of all systematic reviews stating a positive outcome and beneficial potential of the natural treatment or therapy investigated. Conclusion: This living systematic review concludes that there is a growing interest in research pertaining to natural health products and therapies with respect to the prevention of COVID-19 infections and addressing disease severity and mortality, especially in adjunct to conventional medical intervention. Nonetheless, there is a lack of high-quality evidence and consistency in outcome reporting across the large breadth of natural treatment and management options.