In order to detect the immunosuppression status of COVID-19 patients, this study collected blood samples of COVID-19 patients on the 10th, 20th and 30th days after the onset of symptoms, and detected the proinflammatory, anti-inflammatory factors，immunosuppressive marker，immune cells in the blood samples to evaluate the immunosuppression status of COVID-19 patients.

After SARS-CoV-2 infection, the patient's immune system is overactivated. While the immune cells release a large number of proinflammatory factors, anti-inflammatory response starts at the same time. Anti-inflammatory factors such as IL-4, IL-10, and IL-37 will be compensated to resist the release of proinflammatory factors and prevent the further development of systemic inflammatory response. However, when the anti-inflammatory factor is excessively released, it will cause compensatory response syndrome, leading to immunosuppression. Whether the level of anti-inflammatory factors continues to rise, and whether it will lead to the persistence of later immunosuppression is unknown. Therefore, this study intends to recruit COVID-19 patients, detect the pro-inflammatory and anti-inflammatory factors，immunosuppressive marker，immune cells in 10 days, 20days, and 30days after the symptoms appear, and evaluate the immunosuppression status of patients with COVID-19

Inclusion Criteria:

1. Participant is diagnosed with symptomatic COVID-19 by a positive PCR for SARS-CoV-2 or antigen quicktest.
2. Study participant is 18 years of age or older

Exclusion Criteria:

1. Patients with immunosuppression, including HIV infection, hematopoietic stem cell transplantation and high-dose immunosuppressant therapy
2. Pregnancy or breastfeeding
3. Patients receiving chemotherapy or other cancer treatment

Participant is diagnosed with symptomatic COVID-19 by a positive PCR for SARS-CoV-2 or antigen quicktest.