Table 1.

Definitions of This Study

Variables	Definitions
Profession	Including in-service (such as farmers, teacher, pupils, business services, nurses and nannies, waiters, business services, hospital staffs, herdsmen, fisherman, seafarers and long-distance drivers, official staffs, migrant worker, worker, jobless and vagrant persons) and being retired.
A history of chronic diseases	Chronic diseases including chronic cardiovascular disease (i.e., hypertension, coronary heart disease, myocardiopathy, and valvular diseases), chronic liver disease (i.e., chronic hepatitis, liver cirrhosis and liver tumor), chronic metabolic diseases (i.e., obesity, diabetes, fatty liver disease and some cancers), chronic respiratory diseases (i.e., chronic obstructive pulmonary disease and chronic bronchitis), and rheumatic diseases.
A history of surgery	Surgery including all types of human surgery (i.e. tumor enucleation).
Hand hygiene	Referred to hand hygiene practices before the disease onset such as antiseptic hand wash, antiseptic hand rub, or surgical hand antisepsis, and hand-washing frequently, i.e., after contact with animals, before meals, and after using the toilet, etc. Hand hygiene practices including poor hand hygiene (such as not using antiseptic hand wash prepped with 75% alcohol, or not washing hands with soap and water, or other detergents containing an antiseptic agent, or not washing hands frequently after contacting poultry or other animals) and eligible hand hygiene (like using antiseptic handwash prepped with 75% alcohol, or washing hands with soap and water, or other detergents containing an antiseptic agent, or washing hands frequently after contacting poultry or other animals).
A history of smoking	The smoking was defined as 1 cigarette and more per day.
A history of drinking	The drinking was defined as 1 or more drinks at one sitting at least once per week.
First symptoms Patients being treated Patients with loss to follow up	Including cough, expectoration, fever, chest distress, shivering, diarrhea, asthma, headache, pharyngeal pain, abdominal pain, chest pain, and muscle ache. Patients being treated were defined as patients with an antiviral drug therapy during the course of study. Referred to H7N9 patients who could not be investigated such as lost patients and a patient who refused investigation during the course of study.
A random sampling method PaO2/FiO2 ratio (PFR, mmHg) Peak C-reactive protein (CRP)	In this study, the first stage with a random sampling method was to assign a number from 1 to N to each element in all subjects. The next stage was to pick a sample of n of these numbers by using a table of random numbers. By using this method, it must be assured that the numbers chosen were all different, and that none were larger than N. Once the numbers were selected, the individuals corresponding to these numbers were viewed as the sample. PFR is defined as the ratio of arterial oxygen partial pressure to fractional inspired oxygen, and at sea level normal is > 500mmHg. Referred to the value of peak CRP during hospitalization.
Initial white blood cell (WBC) count (109/L)	Including decreased (i.e., WBC count < 3.50), increased (i.e., WBC count > 9.50) and normal (i.e., WBC count is between 3.50 and 9.50) WBC.
Initial neutrophil percentage (INP, %)	Including increased (i.e., INP > 75.0), normal (i.e., INP is between 40.0 and 75.0), and decreased (i.e., INP< 40.0) INP.
Initial lymphocyte percentage (ILP, %)	Including increased (i.e., ILP > 50.0), normal (i.e., ILP is between 20.0 and 50.0), and decreased (i.e., ILP < 20.0) ILP.
Initial value of hemoglobin (IVH, g/L)	Including increased (i.e., IVH > 175.0), normal (i.e., IVH is between 130.0 and 175.0), and decreased (i.e., IVH <130.0) IVH.
Initial blood platelet count (IBPC, 109/L)	Including increased (i.e., IBPC > 350.0), normal (i.e., IBPC is between 125.0 and 350.0), and decreased (i.e., IBPC < 125.0) IBPC.