Weekly Influenza Activity
Kent County, 2007-2008
Collecting Data on Influenza is Not Always Easy
People do not often seek medical attention for the flu; even if they do, physicians do not regularly confirm the diagnosis with a laboratory test. Additionally, parents may report to the schools that their child has the flu, when in fact their child may have a cold or some other infection. Consequently, accurate influenza data can be difficult to obtain and the following data should be interpreted with caution. These data provide a very crude estimate of the occurrence of flu in Kent County. There are 2 types of data that the health department is collecting this year; flu-like illness reports from schools and day care centers and laboratory confirmed influenza reports from physicians.
Flu-Like Illness (school & daycare center reports)
Schools and daycare centers are required by law to provide weekly reports of influenza cases to their local health department. This year schools have been asked to differentiate between “Respiratory Flu”, “Gastrointestinal (Stomach) Flu” and “Other Flu”. The numbers included in the table below are only those cases described as “Respiratory Flu”. These are not laboratory confirmed cases. The data displayed is a weighted average of the percentage of the weekly total enrollment reported to have the "flu" with respiratory symptoms.
Laboratory Confirmed
This data displays the number of laboratory confirmed influenza cases that have been reported to the health department. A case is counted in the week that most closely matches the onset date of illness. Note that the health department may not receive a report of confirmed diagnosis until several weeks after the onset of illness and thus data for any week in the table below could change at anytime. Laboratory tests include “rapid” or “quick” tests performed in offices or clinics which may not be as sensitive or specific as other laboratory methods.Laboratory Confirmed Cases of Influenza, Kent County, 2007-2008
Historical Trends
Influenza activity varies from year to year. Just because the flu season peaked in December in one year does not mean that it will peak in December in the following year. Sometimes the season peaks in January or February. Graphs showing both National Trends and East North Central Trends (which includes Michigan) from the Centers for Disease Control Sentinel Provider Network data; this data helps illustrate that flu season progresses differently each year and it is difficult to predict when the peak activity may occur.
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