tetano
Editor, Senior Moderator
Int J Infect Dis. 2019 Jan 23. pii: S1201-9712(19)30038-4. doi: 10.1016/j.ijid.2019.01.027. [Epub ahead of print]
[h=1]Understanding the complex seasonality of seasonal influenza A and B viruses transmission: Evidence from 6-year surveillance data in Shanghai, China.[/h] Ye C[SUP]1[/SUP], Zhu W[SUP]2[/SUP], Yu J[SUP]3[/SUP], Li Z[SUP]3[/SUP], Zhang Y[SUP]4[/SUP], Wang Y[SUP]2[/SUP], Gu H[SUP]2[/SUP], Zou W[SUP]2[/SUP], Hao L[SUP]5[/SUP], Hu W[SUP]6[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]OBJECTIVES:[/h] Understanding the complexity of influenza subtype seasonality is critical to promoting a suitable vaccination program. Our study aims to identify and compare the seasonality and epidemiological features of seasonal influenza subtypes after the 2009 A/H1N1 pandemic and to lay a foundation for further investigation into the social and environmental factors affecting seasonal influenza transmission.
[h=4]METHODS:[/h] Influenza-like illness (ILI) cases surveillance were conducted in two sentinel hospitals between 2012 and 2018 in Pudong New Area, Shanghai. Weekly data on ILI cases were analyzed. A time series seasonal decomposition analysis was used to reveal the seasonality of influenza and epidemiological features among different subtypes.
[h=4]RESULTS:[/h] In total, 10,977 ILI patients were enrolled, and 2,385 (21.7%) had laboratory-confirmed influenza. Compared to influenza A (16.3%), influenza B (5.4%) was less frequently detected among the ILI patients (p <0.001). During the six-year study period, semiannual epidemic peaks were identified in four years, while only one annual epidemic peak was found in the other two years. An epidemic peak occurred in each winter season, and a secondary peak also occasionally occurred in summer or spring. A/H3N2 predominated in both summer and winter, while A/H1N1, B/Yamagata and B/Victoria circulated almost exclusively in winter or spring. Two lineages of influenza B seem to predominate in alternating years.
[h=4]CONCLUSIONS:[/h] Our study highlights the complexity of seasonal influenza virus activity in a subtropical region of China, presenting both semiannual and annual epidemic peaks in different years. This paper may provide further insight into possible improvements in the timing of influenza vaccinations in Shanghai, China.
Copyright ? 2019. Published by Elsevier Ltd.
[h=4]KEYWORDS:[/h] Influenza; seasonality; surveillance; transmission
PMID: 30684745 DOI: 10.1016/j.ijid.2019.01.027
Free full text
[h=1]Understanding the complex seasonality of seasonal influenza A and B viruses transmission: Evidence from 6-year surveillance data in Shanghai, China.[/h] Ye C[SUP]1[/SUP], Zhu W[SUP]2[/SUP], Yu J[SUP]3[/SUP], Li Z[SUP]3[/SUP], Zhang Y[SUP]4[/SUP], Wang Y[SUP]2[/SUP], Gu H[SUP]2[/SUP], Zou W[SUP]2[/SUP], Hao L[SUP]5[/SUP], Hu W[SUP]6[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]OBJECTIVES:[/h] Understanding the complexity of influenza subtype seasonality is critical to promoting a suitable vaccination program. Our study aims to identify and compare the seasonality and epidemiological features of seasonal influenza subtypes after the 2009 A/H1N1 pandemic and to lay a foundation for further investigation into the social and environmental factors affecting seasonal influenza transmission.
[h=4]METHODS:[/h] Influenza-like illness (ILI) cases surveillance were conducted in two sentinel hospitals between 2012 and 2018 in Pudong New Area, Shanghai. Weekly data on ILI cases were analyzed. A time series seasonal decomposition analysis was used to reveal the seasonality of influenza and epidemiological features among different subtypes.
[h=4]RESULTS:[/h] In total, 10,977 ILI patients were enrolled, and 2,385 (21.7%) had laboratory-confirmed influenza. Compared to influenza A (16.3%), influenza B (5.4%) was less frequently detected among the ILI patients (p <0.001). During the six-year study period, semiannual epidemic peaks were identified in four years, while only one annual epidemic peak was found in the other two years. An epidemic peak occurred in each winter season, and a secondary peak also occasionally occurred in summer or spring. A/H3N2 predominated in both summer and winter, while A/H1N1, B/Yamagata and B/Victoria circulated almost exclusively in winter or spring. Two lineages of influenza B seem to predominate in alternating years.
[h=4]CONCLUSIONS:[/h] Our study highlights the complexity of seasonal influenza virus activity in a subtropical region of China, presenting both semiannual and annual epidemic peaks in different years. This paper may provide further insight into possible improvements in the timing of influenza vaccinations in Shanghai, China.
Copyright ? 2019. Published by Elsevier Ltd.
[h=4]KEYWORDS:[/h] Influenza; seasonality; surveillance; transmission
PMID: 30684745 DOI: 10.1016/j.ijid.2019.01.027
Free full text