Table 1 Inclusion and exclusion criteria
Inclusion criteria | • Aged from 18 to 80 years old • Unlimited gender • Newly developed cough, expectoration, purulent sputum, or exacerbation of original respiratory diseases within 14 days • Meet at least one of the following items:  (1) Fever (> 38 ℃)  (2) Consolidation signs and/or wet rales on chest physical examination  (3) Leucocyte > 10*109/l or < 4*109/l  (4) Patchy infiltration or interstitial changes on chest radiology |
Exclusion criteria | • Highly-suspected of or confirmed with noninfectious lung diseases (tumor, autoimmune diseases, etc.) • The pathogen has been identified • Insufficient respiratory tract or blood specimen • Unable or refusing to cooperate due to physical or psychological factors • Participating in other clinical studies • Investigators or clinicians considers unsafe for the subject to participate |
Exit criteria | • Participants request to withdraw from the interview |