Effects of home quarantine for COVID-19 community control in Shenzhen, China, 2020

Background: Shenzhen implement classification management to prevent and control coronavirus disease 2019 (COVID-19) outbreak. Individuals with epidemic histories (came from Hubei and any other affected regions), but without symptoms were instructed to take home quarantine for 14 days and nucleic acid testing (NAT) for SARS-CoV-2. We described the infection status of the home-quarantined individuals, and effects of community control strategies in the three incubations after Wuhan closure in Shenzhen. Methods: : This was a descriptive research, the sample size was 2,004 individuals based on multistage sampling during the pre-investigation. And the formal investigation expanded the sample size to 57,012 individuals based on pre-investigation. A single throat swab was collected from each individual for nucleic acid testing (NAT) by reverse transcription-polymerase chain reaction (RT-PCR). NAT was performed by a third-party institution. We collected information related to demographics, disease history, travel history, and personal protective measures before home quarantine, and monitored close-contact histories using the We Chat questionnaire. Results: : The total infection rate of home-quarantined individuals was 0.12‰ (95% CI: 0.05‰–0.24‰) out of the total sample size of 59,016. The detection period for seven confirmed cases was primarily concentrated between February 8 and 18, 2020, which was during the second incubation period after Wuhan's closure. The home quarantined individuals with epidemic histories (came from Hubei and any other affected regions) were considered the high risk population during the first two incubations after Wuhan’s closure. No positive cases were detected from February 25 to March 5(the third incubation after Wuhan’s closure). The number of newly-confirmed cases per day was 0 for eight consecutive days from February 22 to 29 in Shenzhen. Conclusions: : The community control strategies for home-quarantined individuals with epidemic histories (came from Hubei and any other affected regions), but without symptoms to take the NAT in the first two incubations is effective to control COVID-19. But it is not advocating for home-quarantined person to take the NAT since the third incubation.