Evaluating Acupuncture as a Therapeutic Intervention for Post-COVID-19 Olfactory Dysfunction: A Systematic Review and Pilot Study

Objective: Olfactory dysfunction (OD) is a common and persistent symptom of Coronavirus disease 2019 (COVID-19) for which effective treatments remain limited. Acupuncture, widely used in Chinese medicine for olfactory disorders has uncertain efficacy in post-COVID-19 OD. Therefore, in this study, we aimed to explore the feasibility and preliminary efficacy of acupuncture in patients with post-COVID-19 OD. Methods: This study was a dual-phased study. Phase I involved a systematic review conducted in accordance with PRISMA guidelines, encompassing eight databases. Phase II consisted of a pilot randomized controlled trial (RCT) enrolling 25 patients with moderate to severe post-COVID-19 OD. Participants were randomly assigned to receive either real (Group A) or sham (Group B) acupuncture. The intervention included eight sessions over four weeks, with assessments at baseline, post-Cycle 1, two-week washout, post-Cycle 2 treatment, and two-week follow-up. The primary outcome was the change in scores on the 12-item Assessment of Self-Reported Olfactory Functioning and Quality of Life (ASOF). Secondary outcomes included the short version of the Questionnaire of Olfactory Disorders-Negative Statements (sQOD-NS) and the Traditional Chinese version of the University of Pennsylvania Smell Identification Test (UPSIT-TC). Results: The systematic review identified 22 studies (15 case reports, 7 RCTs) suggesting that acupuncture may positively influence olfactory function. In the pilot RCT, no significant baseline differences were observed between groups. Group A showed steady improvement across all ASOF domains during Cycle 1 (SOC, mean = 5.86; SRP, mean = 3.26; ORQ, mean = 3.98), with slight declines during Cycle 2 and 2-week follow-up, though scores remained above baseline. Post-Cycle 1, Group A showed higher mean SOC and ORQ scores compared with Group B (7.00 vs. 4.67; 3.98 vs. 3.39). Improvements in secondary outcomes were also more pronounced in Group A, whereas Group B showed minimal changes. Conclusion: Acupuncture appears to be a safe and potentially effective treatment for post-COVID-19 OD, warranting validation through larger clinical trials.