Table 1.

Four types of population screening programs

Personnel Category	Category Description	Troubleshooting Plan
A	1.Coming from Wuhan 2.Those who have recently visited Wuhan in January	The community (village) is used as the unit to investigate the personnel exported from Hubei province, especially Wuhan, and it is required to take the initiative to register with the community (village) health institution, receive regular medical examinations, and actively isolate itself for 14 days. Persons with suspicious symptoms should promptly notify the local health department for screening and screening.
B	People who have contacted A but do not know it (A and B do not know of each other’s existence)	The government publishes the trajectory of confirmed cases in real time. Using big mobile data and the case trajectory applet query function, it is possible to query places where confirmed cases stay online, including flights or railway trips, residential real estate, streets, and shopping malls (supermarkets). Such personnel need to isolate themselves and observe their health status and their family members and contact the CDC of the county (city) where they are located. If there are related suspected symptoms, they should immediately seek medical treatment.
C	Close contacts, family members, friends, colleagues, neighbors	Based on person A, you can find person C, and the district disease control center or community health service center will follow-up with the houses for medical observation.
D	Normal person	Category D personnel reduce going out if conditions permit; reduce contact with As, Cs, or Bs with potential infection; and reduce the possibility of being infected.