The Geographic Synchrony of Seasonal Influenza Waves
Author Information
Author(s): Dena L. Schanzer, Joanne M. Langley, Trevor Dummer, Samina Aziz
Primary Institution: Public Health Agency of Canada
Hypothesis
The study aims to identify the geographic scale at which spatial synchrony exists for influenza A virus across Canada and in relation to the United States.
Conclusion
Local laboratory-based surveillance is needed to accurately assess the level of influenza activity in the community due to weak mixing between regions.
Supporting Evidence
- Influenza epidemics occur annually with peak activity from November to April, affecting 5-20% of the population.
- Regional epidemics were more closely synchronized across the US compared to Canada.
- In three out of six seasons analyzed, the epidemic appeared first in Canada.
Takeaway
The study looks at how flu spreads across Canada and the US, finding that cities and rural areas often get sick at the same time, but sometimes they don't.
Methodology
Weekly laboratory confirmations for influenza A were obtained from the Canadian FluWatch and the US FluView surveillance programs from 1997/98 to 2006/07.
Potential Biases
Potential bias due to varying influenza testing procedures and reporting practices across jurisdictions.
Limitations
The study is limited by the lack of detailed geo-coding of laboratory confirmed influenza cases for some communities and the small number of confirmed cases for many cities.
Participant Demographics
The study included data from various Canadian provinces and US surveillance regions, with a focus on urban and rural areas.
Digital Object Identifier (DOI)
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