Management and infection of close contacts
Because all the discharged patients were put under centralized quarantine for 14 days at health care facilities, only 26 positive retest patients had close contacts, and 148 close contacts were traced.Table 4 presents the characteristics of positive retest patients and close contacts. The demographic characteristics of the 148 close contacts were as follows: sex distribution was more male (89, 60.1%) than female (59, 39.9%); all age groups were included, and 18 to 44 years old accounted for most of the close contact (92, 62.2%). A total of 137 (92.6%) close contacts were quarantined at health care facilities, and 11 (7.4%) close contacts quarantined at home. Among all close contacts, 41.2% (61/148) were public transportation contacts, 28.4% (42/148) were household contacts, 21.0% (31/148) were entertainment place contacts, 8.1% (12/148) were workplace contacts and 1.4% (2/148) were healthcare setting contacts. Positive retest patients with moderate severity had the closest contacts (96, 64.9%), followed by asymptomatic patients (40, 27.0%). After quarantine for 12.0 days (IQR, 6.0 to 14.0 days) at a health care facility or at home and 4.5 times (IQR, 3.0 to 10.0 times) of RT-PCR testing, 148 close contacts tested negative for SARS-CoV-2 RNA, and no suspicious clinical symptoms were reported.