In the sixth edition of the treatment protocol for novel coronavirus pneumonia (trial version), the treatment of severe and critically ill cases includes the addition of “plasma therapy for recovered patients”. The protocol states that plasma from recovered patients can be used to treat patients with rapid disease progression, severe and critical forms. It is best to treat patients within 2 weeks of disease onset, when there is still viral replication or viremia in the patient’s body. The use of recovery plasma can quickly neutralize the virus in the blood, reduce the inflammatory response, and improve the prognosis. After 2 weeks of disease onset, the viral load in the patient’s body is significantly reduced, and serious complications may have occurred, such as bacterial infection, coagulation dysfunction, multi-organ failure, and massive damage to alveolar epithelial cells, or even total destruction, and treatment with plasma at this time cannot achieve the desired effect.