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China CDC Wkly
. 2023 Dec 8;5(49):1100-1106.
doi: 10.46234/ccdcw2023.206. Nowcasting and Forecasting Seasonal Influenza Epidemics - China, 2022-2023
Zhanwei Du 1 2 , Zengyang Shao 2 , Xiao Zhang 2 , Ruohan Chen 2 , Tianmu Chen 3 , Yuan Bai 1 2 , Lin Wang 4 , Eric H Y Lau 5 , Benjamin J Cowling 1 2
Affiliations
Background: Seasonal influenza resurged in China in February 2023, causing a large number of hospitalizations. While influenza epidemics occurred across China during the coronavirus disease 2019 (COVID-19) pandemic, the relaxation of COVID-19 containment measures in December 2022 may have contributed to the spread of acute respiratory infections in winter 2022/2023.
Methods: Using a mathematical model incorporating influenza activity as measured by influenza-like illness (ILI) data for northern and southern regions of China, we reconstructed the seasonal influenza incidence from October 2015 to September 2019 before the COVID-19 pandemic. Using this trained model, we predicted influenza activities in northern and southern China from March to September 2023.
Results: We estimated the effective reproduction number R e as 1.08 [95% confidence interval ( CI): 0.51, 1.65] in northern China and 1.10 (95% CI: 0.55, 1.67) in southern China at the start of the 2022-2023 influenza season. We estimated the infection attack rate of this influenza wave as 18.51% (95% CI: 0.00%, 37.78%) in northern China and 28.30% (95% CI: 14.77%, 41.82%) in southern China.
Conclusions: The 2023 spring wave of seasonal influenza in China spread until July 2023 and infected a substantial number of people.
Keywords: China; Forecasting; Influenza.
. 2023 Dec 8;5(49):1100-1106.
doi: 10.46234/ccdcw2023.206. Nowcasting and Forecasting Seasonal Influenza Epidemics - China, 2022-2023
Zhanwei Du 1 2 , Zengyang Shao 2 , Xiao Zhang 2 , Ruohan Chen 2 , Tianmu Chen 3 , Yuan Bai 1 2 , Lin Wang 4 , Eric H Y Lau 5 , Benjamin J Cowling 1 2
Affiliations
- PMID: 38125915
- PMCID: PMC10728554
- DOI: 10.46234/ccdcw2023.206
Background: Seasonal influenza resurged in China in February 2023, causing a large number of hospitalizations. While influenza epidemics occurred across China during the coronavirus disease 2019 (COVID-19) pandemic, the relaxation of COVID-19 containment measures in December 2022 may have contributed to the spread of acute respiratory infections in winter 2022/2023.
Methods: Using a mathematical model incorporating influenza activity as measured by influenza-like illness (ILI) data for northern and southern regions of China, we reconstructed the seasonal influenza incidence from October 2015 to September 2019 before the COVID-19 pandemic. Using this trained model, we predicted influenza activities in northern and southern China from March to September 2023.
Results: We estimated the effective reproduction number R e as 1.08 [95% confidence interval ( CI): 0.51, 1.65] in northern China and 1.10 (95% CI: 0.55, 1.67) in southern China at the start of the 2022-2023 influenza season. We estimated the infection attack rate of this influenza wave as 18.51% (95% CI: 0.00%, 37.78%) in northern China and 28.30% (95% CI: 14.77%, 41.82%) in southern China.
Conclusions: The 2023 spring wave of seasonal influenza in China spread until July 2023 and infected a substantial number of people.
Keywords: China; Forecasting; Influenza.