Clinical Study on the Immune Response Characteristics of Novel Coronavirus and Influenza Virus Infection

Inclusion Criteria: 1. volunteers aged 18 years and above at the time of screening; 2. informed consent obtained from volunteers and volunteers/witnesses able to sign the informed consent form; 3. an interval of ≥3 months from the last COVID-19 or influenza vaccination; 4. an interval of ≥ 3 months from the last respiratory viral infection such as COVID-19 or Influenza virus occurs; 5.1 cohort 1：novel coronavirus virus antigen-positive and within 48 hours of onset of symptoms of infection; 5.2 cohort 2：influenza virus antigen-positive and within 48 hours of onset of symptoms of infection; 5.3 cohort 3：novel coronavirus and influenza virus antigen-negative, no febrile symptoms, and no symptoms of viral or bacterial respiratory infections. Exclusion Criteria: 1. known or suspected concomitant more serious and medically unstable disease in the judgment of the investigator, including: respiratory disease, tuberculosis, acute infections or active chronic disease, hepatic or renal disease, cardiovascular disease (cardiorespiratory failure), hypertension (systolic blood pressure ≥160 mmHg, diastolic blood pressure ≥100 mmHg), malignant tumors, infectious or allergic skin diseases, and the presence of HIV infection; 2. Absence of spleen or functional absence of spleen; 3. immunosuppressive therapy, anti-allergy therapy, cytotoxic therapy, inhaled corticosteroids (excluding corticosteroid spray therapy for allergic rhinitis, and superficial corticosteroid therapy for acute uncomplicated dermatitis) within the past 6 months; 4. Received blood products within the past 3 months; 5. has received other vaccines or investigational drugs within the past 1 month; 6. is receiving anti-tuberculosis treatment; 7. In the judgment of the investigator, due to a variety of medical, psychological, social, or other conditions that are contrary to the trial protocol or that affect the signing of informed consent by the volunteer.