"Low-risk groups" deserve more attention than "high-risk groups" in imported COVID-19 cases

Wanshan Zheng; Ying Tan; Zedi Zhao; Jin Chen; Xiaomei Dong; Xiongfei Chen

doi:10.3389/fmed.2023.1293747

"Low-risk groups" deserve more attention than "high-risk groups" in imported COVID-19 cases

Front Med (Lausanne). 2023 Nov 30:10:1293747. doi: 10.3389/fmed.2023.1293747. eCollection 2023.

Authors

Wanshan Zheng¹, Ying Tan¹, Zedi Zhao¹, Jin Chen¹, Xiaomei Dong¹, Xiongfei Chen²

Affiliations

¹ Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, Guangdong, China.
² Guangzhou Center for Disease Control and Prevention, Guangzhou, Guangdong, China.

Abstract

Objective: To estimate the optimal quarantine period for inbound travelers and identify key risk factors to provide scientific reference for emerging infectious diseases.

Methods: A parametric survival analysis model was used to calculate the time interval between entry and first positive nucleic acid test of imported cases in Guangzhou, to identify the influencing factors. And the COVID-19 epidemic risk prediction model based on multiple risk factors among inbound travelers was constructed.

Results: The approximate 95th percentile of the time interval was 14 days. Multivariate analysis found that the mean time interval for inbound travelers in entry/exit high-risk occupations was 29% shorter (OR 0.29, 95% CI 0.18-0.46, p < 0.0001) than that of low-risk occupations, those from Africa were 37% shorter (OR 0.37, 95% CI 0.17-0.78, p = 0.01) than those from Asia, those who were fully vaccinated were 1.88 times higher (OR 1.88, 95% CI 1.13-3.12, p = 0.01) than that of those who were unvaccinated, and those in other VOC periods were lower than in the Delta period. Decision tree analysis showed that a combined entry/exit low-risk occupation group with Delta period could create a high indigenous epidemic risk by 0.24.

Conclusion: Different strata of imported cases can result in varying degrees of risk of indigenous outbreaks. "low-risk groups" with entry/exit low-risk occupations, fully vaccinated, or from Asia deserve more attention than "high-risk groups."

Keywords: COVID-19; imported case; quarantine period; risk factor; time interval.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by grant 2020YFC2002904 from the National Key Research and Development Program of China.