Report the case 24 hours in advance, and take "3+ 1 1" health management measures within 48 hours with negative proof of nucleic acid test, that is, family health monitoring for 3 days+1 1 day, and follow-up health monitoring at 1, 2, 4, 5, 6 and 7. Those who are not reported will be persuaded to return, and those who fail to persuade will be given a yellow code.