tetano
Editor, Senior Moderator
J Thorac Dis
. 2025 Jul 31;17(7):4732-4745.
doi: 10.21037/jtd-24-1703. Epub 2025 Jul 28. Epidemiological features and risk factors of SARS-CoV-2 reinfection: a retrospective cohort analysis in Xiamen, China
Yunkang Zhao[SUP] #[/SUP][SUP] 1 [/SUP], Yao Wang[SUP] #[/SUP][SUP] 1 [/SUP], Yidun Zhang[SUP] #[/SUP][SUP] 2 [/SUP], Zeyu Zhao[SUP] 1 [/SUP], Buasiyamu Abudunaibi[SUP] 1 [/SUP], Kang Fang[SUP] 1 [/SUP], Huimin Qu[SUP] 1 [/SUP], Qiao Liu[SUP] 1 [/SUP], Yanhua Su[SUP] 1 [/SUP], Chenghao Su[SUP] 2 3 [/SUP], Zhinan Guo[SUP] 2 [/SUP], Tianmu Chen[SUP] 1 [/SUP]
Affiliations
Background: Recently, surges in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfections in China have raised public concern. We investigated the epidemiological features and risk factors for SARS-CoV-2 reinfection in China.
Methods: A retrospective cohort study was conducted in Xiamen, China (2021-2023) with two subcohorts: Delta-Omicron (cohort 1) and Omicron-Omicron (cohort 2). Descriptive analysis and ensemble modeling were employed to evaluate reinfections.
Results: A total of 327 cases without fatalities were included. Reinfections accounted for 14.68% of cases, with 22.51% in cohort 1 and 3.68% in cohort 2. Compared with primary infections (PIs) (99.69% symptomatic, 56.54% hospitalized), reinfections were less severe, with fewer symptomatic instances (47.92%) and hospitalizations (4.65%). The majority of reinfections (83.33%) occurred following the relaxation of strict public health and social measures. The median time interval between PI and reinfection was longer for cohort 1 (462 days) than for cohort 2 (280 days). Reinfection risks were noted among lesser developed regions, those without persistent PI, those with primary Delta variant infection, government and hospital workers, and unvaccinated individuals.
Conclusions: SARS-CoV-2 reinfections are generally less severe and are influenced by the relaxation of control measures, viral evolution, and changing patterns of population immunity and contact; this underscores the need for ongoing surveillance and targeted public health strategies to manage future infection waves.
Keywords: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); coronavirus disease 2019 (COVID-19); primary infection (PI); reinfection.
. 2025 Jul 31;17(7):4732-4745.
doi: 10.21037/jtd-24-1703. Epub 2025 Jul 28. Epidemiological features and risk factors of SARS-CoV-2 reinfection: a retrospective cohort analysis in Xiamen, China
Yunkang Zhao[SUP] #[/SUP][SUP] 1 [/SUP], Yao Wang[SUP] #[/SUP][SUP] 1 [/SUP], Yidun Zhang[SUP] #[/SUP][SUP] 2 [/SUP], Zeyu Zhao[SUP] 1 [/SUP], Buasiyamu Abudunaibi[SUP] 1 [/SUP], Kang Fang[SUP] 1 [/SUP], Huimin Qu[SUP] 1 [/SUP], Qiao Liu[SUP] 1 [/SUP], Yanhua Su[SUP] 1 [/SUP], Chenghao Su[SUP] 2 3 [/SUP], Zhinan Guo[SUP] 2 [/SUP], Tianmu Chen[SUP] 1 [/SUP]
Affiliations
- PMID: 40809228
- PMCID: PMC12340267
- DOI: 10.21037/jtd-24-1703
Background: Recently, surges in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfections in China have raised public concern. We investigated the epidemiological features and risk factors for SARS-CoV-2 reinfection in China.
Methods: A retrospective cohort study was conducted in Xiamen, China (2021-2023) with two subcohorts: Delta-Omicron (cohort 1) and Omicron-Omicron (cohort 2). Descriptive analysis and ensemble modeling were employed to evaluate reinfections.
Results: A total of 327 cases without fatalities were included. Reinfections accounted for 14.68% of cases, with 22.51% in cohort 1 and 3.68% in cohort 2. Compared with primary infections (PIs) (99.69% symptomatic, 56.54% hospitalized), reinfections were less severe, with fewer symptomatic instances (47.92%) and hospitalizations (4.65%). The majority of reinfections (83.33%) occurred following the relaxation of strict public health and social measures. The median time interval between PI and reinfection was longer for cohort 1 (462 days) than for cohort 2 (280 days). Reinfection risks were noted among lesser developed regions, those without persistent PI, those with primary Delta variant infection, government and hospital workers, and unvaccinated individuals.
Conclusions: SARS-CoV-2 reinfections are generally less severe and are influenced by the relaxation of control measures, viral evolution, and changing patterns of population immunity and contact; this underscores the need for ongoing surveillance and targeted public health strategies to manage future infection waves.
Keywords: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); coronavirus disease 2019 (COVID-19); primary infection (PI); reinfection.