ORIGINAL RESEARCH article
Front. Public Health
Sec. Infectious Diseases: Epidemiology and Prevention
Volume 13 - 2025 | doi: 10.3389/fpubh.2025.1589683
This article is part of the Research TopicSARS-CoV-2: Virology, Epidemiology, Diagnosis, Pathogenesis and Control, Volume IIView all 7 articles
Associated factors in SARS-CoV-2 infection among close contacts during the zero-COVID policy from 2020 to 2022 in the northeast of Shenzhen, China: A retrospective Cohort Study
Provisionally accepted
- Longgang Center for Diseases Control and Prevention, Shenzhen, China
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Background: Identifying high-risk groups and developing specific interventions is essential to combat pandemic including COVID-19. We estimated key factors of demographic characteristic, exposure-related variables, and vaccination status in secondary infection among close contacts throughout the zero-COVID policy; Methods: We used contact tracing data from 622 primary cases and 31278 close contacts between February 2020 and December 2022 in the northeast of ShenZhen, China. The multivariate logistic regression was utilized to identify factors affecting SARS-CoV-2 infection of close contacts;Results: The secondary attack rate (SAR) of close contacts was 1.4% (95% CI:1.3%-1.5%), and the associated factors included over 50 (OR=1.47, 95% CI: 2 / 24 1.13-1.91), living in urban village housing (OR=1.51, 95% CI: 1.04-2.19), closer relationship with primary cases (e.g., household members: OR=44.06, 95% CI: 34.45-56.36), last exposure occurring before the illness onset of cases (e.g., > 2 days before: OR=0.52, 95% CI: 0.27-1.00), exposed to cases with moderate symptoms (OR=0.62, 95% CI: 0.40-0.95), and better COVID-19 vaccination status (e.g., booster vaccination within 6 months before the last exposure: OR=0.38, 95% CI: 0.24-0.60); Conclusions: Our findings should be helpful to develop targeted surveillance and interventions for these high-risk groups to understand ongoing COVID-19 issue and improve future pandemic management.
Keywords: Close contacts, SARS-CoV-2, Associated factors, Vaccination, Secondary attack rate 1.Introduction
Received: 07 Mar 2025; Accepted: 26 May 2025.
Copyright: © 2025 Zeng, Xv and Cui. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Li Cui, Longgang Center for Diseases Control and Prevention, Shenzhen, China
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