In December 2019, the coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan, China, and rapidly spread across the globe (Singhal, 2020). This pandemic has significantly impacted communities worldwide, highlighting the virus's continuous spread and mutation, which remains a persistent threat to humanity (Birch et al., 2021). Initial treatment for COVID-19 is conventional Western medicine (CWM), including antiviral agents, antibacterial drugs, and supportive therapy (Mahalakshmi et al., 2021). However, these drugs have poor efficacy in preventing and controlling COVID-19, especially in the treatment of neurological manifestations, and some drugs have severe adverse reactions (Tsang et al., 2021). Thus, exploring new therapeutic strategies is urgently needed (Ding et al., 2020).

As the pandemic has progressed, notable subsets of patients have experienced protracted symptoms post-recovery, commonly referred to as long-haul syndrome, long-COVID, or post-COVID syndrome (Mehandru and Merad, 2022). The Centres for Disease Control and Prevention (CDC) defines ‘post-COVID conditions’ as any health consequences occurring more than 4 weeks post-SARS-CoV-2 infection, with long-COVID typically encompassing symptoms that persist for more than 3 months after the initial infection, which cannot be explained by other diagnoses (Yong, 2021). One study categorised individuals as long-haulers if they remained symptomatic 6–9 months post-COVID-19 (Ali et al., 2022).

The transition of COVID-19 from acute infection to a persistent, chronic condition has underscored the necessity for expanded research into effective therapeutic options. This shift has prompted an exploration of Traditional Chinese Medicine (TCM) as a viable complementary approach to both acute and ongoing symptoms associated with long-COVID (Taylor-Swanson et al., 2022). TCM has been extensively used for thousands of years to treat various diseases and offers a novel strategy for the pandemic's challenges (Wang et al., 2021a).

According to syndrome differentiation in TCM theory, the conditions often seen in long-COVID, including fatigue and muscle pain, among other symptoms, can be attributed to Qi deficiency and dampness-stasis (Lozano, 2022). Chinese herbal medicines such as Huáng Qí (Astragalus), Gān Căo (Radix glycyrrhizae), and Cāng Zhú (Atractylodis) are known for their effects of nourishing Qi and clearing dampness. Clinical evidence suggests that TCM plays a positive role in improving these symptoms, potentially reducing adverse effects induced by Western medical drugs and improving clinical prognosis for patients with mild infections (Beyerstedt et al., 2021; Yin et al., 2021).

The meta-analysis and the retrospective study both underscore the holistic approach of TCM in treating COVID-19 and its sequelae. The meta-analysis provides evidence of TCM’s wide-ranging effects on viral, inflammatory, and immunological pathways, detailing the antiviral, anti-inflammatory, and immunomodulatory mechanisms of TCM, signifying its potential as an effective remedy for the complex and varied symptoms of long-COVID (Hu et al., 2021, Liu et al., 2021). This will corroborate the retrospective study's findings that a single TCM formula (QDQF1 Mod. 3) effectively addresses a spectrum of long-COVID symptoms (Zhang et al., 2020a, Huang et al., 2021).