Analysis of multiplex pathogen sentinel surveillance results of SARS-CoV-2 and influenza virus in Sichuan Province, 2024–2026
- 1Sichuan Center for Disease Control and Prevention
Abstract
Objective: To analyze the epidemiological characteristics and coinfection of SARS-CoV-2 and influenza virus among acute respiratory infection (ARI) cases in Sichuan Province from August 2024 to July 2026.
Methods: Using 24-month surveillance data from seven national respiratory pathogen sentinel hospitals in Sichuan Province, respiratory specimens were tested for both viruses by multiplex real-time RT-PCR. Positive rates and 95% CIs were calculated by the Wilson score method; group comparisons used the chi-square test or Fisher’s exact test; independent risk factors were identified by multivariable logistic regression.
Results: A total of 22,436 valid cases were included. The positive rates of SARS-CoV-2, influenza virus, and coinfection were 4.39% (95% CI: 4.13–4.67%), 9.83% (95% CI: 9.45–10.22%), and 0.05% (95% CI: 0.03–0.09%), respectively. The two viruses peaked in different seasons, with SARS-CoV-2 in summer and influenza in winter–spring. Summer was an independent risk factor for SARS-CoV-2 infection (OR = 23.88, 95% CI: 17.04–33.46); children aged 6–14 years had the highest risk of influenza (OR = 2.52, 95% CI: 2.21–2.88). The observed coinfection rate was far lower than the expectation under independent circulation of the two viruses (0.43%; O/E = 0.11, p < 0.001), indicating a negative (asynchronous) association rather than synergy, with marked spatiotemporal clustering.
Conclusion: SARS-CoV-2 and influenza virus circulated in pronounced seasonal asynchrony in Sichuan Province, with no population-level evidence of synergy; coinfection was rare but locally clustered, supporting differentiated prevention and control strategies. Given the hospital-based sentinel design, extrapolation to the whole province should be made with caution.
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BibTeX
@article{hu2026analysis,
title = {{Analysis of multiplex pathogen sentinel surveillance results of SARS-CoV-2 and influenza virus in Sichuan Province, 2024–2026}},
author = {Fengmiao Hu and Xingyu Zhou and Lijun Zhou and Zhirui Li and Shuang Dong and Chongkun Xiao},
journal = {Frontiers in Public Health},
year = {2026},
month = oct,
doi = {10.3389/fpubh.2026.1961515},
url = {https://www.frontiersin.org/articles/10.3389/fpubh.2026.1961515/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Analysis of multiplex pathogen sentinel surveillance results of SARS-CoV-2 and influenza virus in Sichuan Province, 2024–2026
AU - Fengmiao Hu
AU - Xingyu Zhou
AU - Lijun Zhou
AU - Zhirui Li
AU - Shuang Dong
AU - Chongkun Xiao
PY - 2026
DA - 2026/10/20
JO - Frontiers in Public Health
DO - 10.3389/fpubh.2026.1961515
UR - https://www.frontiersin.org/articles/10.3389/fpubh.2026.1961515/full
AB - Objective: To analyze the epidemiological characteristics and coinfection of SARS-CoV-2 and influenza virus among acute respiratory infection (ARI) cases in Sichuan Province from August 2024 to July 2026. Methods: Using 24-month surveillance data from seven national respiratory pathogen sentinel hospitals in Sichuan Province, respiratory specimens were tested for both viruses by multiplex real-time RT-PCR. Positive rates and 95% CIs were calculated by the Wilson score method; group comparisons used the chi-square test or Fisher’s exact test; independent risk factors were identified by multivariable logistic regression. Results: A total of 22,436 valid cases were included. The positive rates of SARS-CoV-2, influenza virus, and coinfection were 4.39% (95% CI: 4.13–4.67%), 9.83% (95% CI: 9.45–10.22%), and 0.05% (95% CI: 0.03–0.09%), respectively. The two viruses peaked in different seasons, with SARS-CoV-2 in summer and influenza in winter–spring. Summer was an independent risk factor for SARS-CoV-2 infection (OR = 23.88, 95% CI: 17.04–33.46); children aged 6–14 years had the highest risk of influenza (OR = 2.52, 95% CI: 2.21–2.88). The observed coinfection rate was far lower than the expectation under independent circulation of the two viruses (0.43%; O/E = 0.11, p < 0.001), indicating a negative (asynchronous) association rather than synergy, with marked spatiotemporal clustering. Conclusion: SARS-CoV-2 and influenza virus circulated in pronounced seasonal asynchrony in Sichuan Province, with no population-level evidence of synergy; coinfection was rare but locally clustered, supporting differentiated prevention and control strategies. Given the hospital-based sentinel design, extrapolation to the whole province should be made with caution.
SN - 2296-2565
ER -