A randomized, controlled trial of ozone therapy for Post-COVID-19 Condition (long COVID)

INTERVENTION: Ozone therapy group:the subjects received not only routine treatment according to their condition, but also ozone therapy (autohemotransfusion). The amount of venous blood collected was 100ml on the first day, and increased to 200ml on the next day. Each treatment involves same volume blood and ozone, with a 20‐50 µg/mL ozone concentration, once a day, and last 10 days.;Normal therapy group:the subjects received routine treatment according to their condition without ozone therapy.; CONDITION: Post‐COVID‐19 Condition (long COVID) PRIMARY OUTCOME: Comprehensive symptom score;Lung function test;Radiographic score of chest CT; SECONDARY OUTCOME: laboratory results;STOP‐Bang, ESS, PSQI, ISI;Anxiety and depression mood scale score; INCLUSION CRITERIA: (1) male or female adults, with age of 18 ‐70 years; (2) having been infected with confirmed SARSCoV‐2 infection three months ago; (3) having persistent symptoms from onset and lasting for at least 4 weeks which cannot be explained by an alternative diagnosis; (4) the body temperature has returned to normal after the acute period treatment, in the recovery period but still have symptoms, such as cough, expectoration, sore throat, fatigue, smell disorder, muscle soreness, etc; or there are still residual imaging features remained after COVID‐19 infection; or there are still psychological symptoms remained such as insomnia, anxiety, irritability, sweating, etc; (5) The participant himself signs the informed consent form and agrees to collect the clinical samples.