This study is a prospective cohort study aimed to clarify the continuous immune state changes of patients with COVID-19. Investigators include the patients admitted to the hospital within one week after the onset of COVID-19. 10ml of patients' blood was collected day 1, day 7, day 14 , and day 20 after the patients admitted to the hospital. The blood inflammatory factors, immune related molecules, and immune cells were detected to determine the changes of patients' immune status. The impact of immune status changes on prognosis and quality of life in later follow-up period was evaluated by various questionnaires and evaluation scales.

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 interleukin 4 (IL-4), interleukin 10 (IL-10) and interleukin 37 (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 patients infected with novel coronavirus to enter the hospital within one week of onset, and collect 10ml of patients' blood on the first, seventh, fourteenth and twentieth day after the patients feel the hospital feeling, respectively, to detect the blood inflammatory factors, immune related molecules and immune cells, and determine the changes of patients' immune status. The patients were followed up for 2 and 6 months after arriving at the hospital to conduct self-reported symptom questionnaire, health related quality of life (HRQoL) questionnaire, Hospital Anxiety and Depression Scale (HADS), and other questionnaires and scales to assess the impact of changes in the patient's immunological status on the prognosis and later quality of life.

Inclusion Criteria:

1. Patients diagnosed as novel coronavirus infection by PCR or antigen rapid detection for the first time
2. Patients hospitalized within one week after the occurrence of clinical symptoms related to novel coronavirus infection (fever, cough, shortness of breath or dyspnea, fatigue, headache, muscle or body pain, sore throat, nasal congestion or runny nose, chills, nausea, vomiting, diarrhea, mental state changes)
3. Age over 18, gender unlimited

Exclusion Criteria:

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

Participant is diagnosed with symptomatic COVID-19 by a positive PCR or rapid antigen detection for SARS-CoV-2 and with treatment in hospital