The challenges in symptomatic therapy of post-COVID-19: a Bulgarian cohort study

Background : Post-COVID syndrome encompasses a spectrum of persistent symptoms following acute SARS-CoV-2 infection. Fatigue, cognitive disturbances, and musculoskeletal complaints are among the most commonly reported symptoms. Emerging evidence suggests a role of immune dysregulation, autoantibody production, and micronutrient deficiencies in the pathogenesis of post-COVID. Objective : To evaluate the clinical presentation, autoimmunity profile, vitamin D status, and response to targeted supplementation in a small cohort of patients with post-COVID syndrome. Aim : Text. Methods : Fourteen patients meeting clinical criteria for post-COVID syndrome (mean age 39.79 ± 5.49 years) were enrolled. ANA testing was performed in 13 patients, and serum vitamin D levels were assessed in 12. Eight patients received a supplementation protocol consisting of melatonin, N-acetylcysteine (NAC), 5-HTP, and vitamin D. Clinical improvement was evaluated at follow-up. Results : The most common symptoms were fatigue (64.3%), blurred vision (57.1%), musculoskeletal pain (57.1%), brain fog (50.0%), and sleep disturbances (50.0%). ANA positivity was detected in 61.5% of the tested patients, although individuals with diagnosed autoimmune diseases were excluded after rheumatological consultation. Vitamin D deficiency or low levels were identified in 58.4% of patients. Among those who received supplementation and were available for follow-up (n = 5), 80% reported clinical improvement. The association between supplementation and symptom improvement did not reach statistical significance (p = 0.576), likely due to the small sample size. Conclusion : Patients with post-COVID syndrome may exhibit signs of subclinical autoimmunity and vitamin D insufficiency. Supplementation with immunomodulatory and antioxidant agents may provide symptomatic benefit and warrants further investigation in larger, controlled studies.