A Systematic Review of Trials Currently Investigating Therapeutic Modalities for Post-Acute COVID-19 Syndrome and Registered on World Health Organization International Clinical Trials Platform

Author Department

Internal Medicine; Medicine

Document Type

Article, Peer-reviewed

Publication Date



Background: Post-acute coronavirus 2019 (COVID-19) syndrome (PACS) is a well-recognized complex systemic disease that is associated with substantial morbidity. There is a paucity of established interventions to treat patients with this syndrome.

Objectives: To systematically review registered trials currently investigating therapeutic modalities for PACS.

Data sources: Search was conducted up to the 16th of September 2022 using the COVID-19 section of the World Health Organization (WHO) Internal Clinical Trials Registry Platform.

Study eligibility criteria, participants, and interventions: Interventional clinical trials of any sample size examining any therapeutic modality targeting persistent symptoms among individuals after diagnosis with COVID-19.

Methods: Data on trial characteristics and intervention characteristics were collected and summarized.

Results: After screening 17125 trials, 388 trials from 42 countries were eligible. 331 trials tested mono-therapeutic strategies, while 39 trials included a combination of interventions. Among the 824 primary outcomes identified, there were more than 300 different outcomes. Rehabilitation was the most employed class of intervention with 169 trials. We encountered 76 trials examining pharmacological agents of various classes with the most common agent being colchicine. Complementary and alternative medicine encompassed 64 trials exploring Traditional Chinese Medicine, Ayurveda, homeopathic medications, naturopathic medications, vitamins, dietary supplements, and botanicals. Psychotherapeutic and educational interventions were also employed with 12 and 4 trials, respectively. Other interventions including transcranial current direct stimulation, transcutaneous auricular vagus nerve stimulation, general electrical stimulation, cranial electrotherapy stimulation, various stem cell interventions, and oxygen therapy interventions were also employed.

Conclusion: We identified 388 registered trials with a high degree of heterogeneity exploring 144 unique interventions for PACS. Most target general alleviation of symptoms. There is a need for further high-quality and methodologically robust PACS treatment trials conducted with standardization of outcomes while following WHO's recommendation for uniform evaluation and treatment.

Keywords: COVID-19; Coronavirus; Long COVID; Post-acute COVID-19 syndrome; SARS-CoV-2.