Treatment
Patients in the demeclocycline 150 mg daily group and demeclocycline 300 mg daily group (administered as 150 mg twice daily) received the study drug orally in the form of demeclocycline 150 mg capsules for a period of 14 days. The concurrent use of corticosteroids, including dexamethasone, immunosuppressants, and immunostimulants, or biologics, such as vaccines and antibody drugs, was prohibited during the study treatment, except for sotrovimab or casirivimab plus imdevimab. If a patient required the administration of dexamethasone due to the exacerbation of COVID-19, the study treatment was discontinued.