Communicable Disease

Monitoring Influenza in Kent County

In General

Over the past three decades, influenza has caused an average of 23,607 deaths a year in the United States (range 3,349 to 48,614).  More than 200,000 people have to be admitted to the hospital each year as a result of influenza.  Seasonal influenza infections are generally more common among children, however, individuals 65 years of age and older are more likely to suffer from severe illness, potentially leading to death. In Kent County, there were 78 deaths in 2009 from influenza or pneumonia; 80 percent of these deaths occurred in the population 65 years of age and older. Influenza/pneumonia was the 8th most common cause of death in Kent County in 2009.

Last Year

During 2010-11, influenza season peaked during the third week of February among lab confirmed cases in Kent County. Influenza activity also peaked during the third week of February among cases of influenza-like illness reported to the Michigan Department of Community Health and U.S. Centers for Disease Control. Typically, influenza activity peaks sometime between January and March. 
Reports of respiratory flu at schools and daycare centers, as well as Michigan Syndromic Surveillance system emergency room respiratory complaints peaked during the third week of March. A review of data reported to the health department during that time frame shows there was a mix of respiratory cases such as Streptococcal Disease, Invasive Group A; Streptococcus pneumoniae, Invasive; Coccidiodmycosis, Pertussis, and Tuberculosis cases reported. This data indicates that a wide range of other respiratory infections were occurring in Kent County in March 2011.

Additional data on the 2010-2011 influenza season can be found at the following link: Kent County Influenza Summary Report, 2010-2011

This Year

Although it is impossible to predict how this year’s influenza season will compare to last year’s, the Health Department will continue using its three-part comprehensive plan that will focus on surveillance, prevention/control of influenza, and public education.
The Epidemiology unit is responsible for conducting effective and timely influenza surveillance in Kent County. This entails collecting, analyzing, interpreting, and disseminating influenza data. Epidemiologists study the frequency, pattern and causes of influenza and influenza outbreaks in the Kent County population. They ask and try to answer the “who, what, when, where, why, and how” questions.

Surveillance

There are three main goals of influenza surveillance:

  1. To provide epidemiologic information during the annual influenza season to measure the development and seriousness of each influenza season;
  2. To monitor changes in circulating viruses;
  3. Determine the magnitude of influenza illness in the county in order to guide the actions of county public health officials.

KCHD monitors influenza in several ways:

  1. Physician reports of influenza- Influenza is an officially reportable condition that is required by state law to be reported to the KCHD.
  2. Laboratory reports of influenza- Labs are required by law to report confirmed results to the local health department
  3. Infection Control Departments - The KCHD has requested that local hospital Infection Control Departments report confirmed cases of influenza to the KCHD.
  4. Daycares, schools and camps - are required by law to report the weekly total number of cases of influenza to the KCHD.
  5. “Sentinel” providers - physicians who have agreed to report cases of “influenza-like” illness visits by age group, and the total number of “influenza-like” visits per week
  6. Emergency Departments – KCHD has access to chief complaint data from Kent County emergency departments, which allows for us to track patients visiting the EDs for flu-like symptoms.

The Kent County Health Department also monitors influenza activity at the state, national, and global levels. Information that is collected in Kent County is reported to the state health department. The data is then forwarded on to the CDC.

Data collection, analysis, interpretation, and dissemination

Following the receipt of confirmed cases of influenza from labs, physicians, and hospital infection control departments, the data will be entered into a database. From October through May, surveillance information will be updated weekly. Aggregate data on confirmed cases and school reporting data will be available on the Kent County Health Department’s web site (www.stickittotheflu.com). An epidemiologist will analyze and interpret data and determine how the data relates to trends seen at the state and national levels.

Information For Health Care Providers

  • Timely (weekly) surveillance updates will be posted on the Kent County website on the Health Department’s web page.
  • Clinical signs and symptoms of influenza

Conclusion

While no intervention is likely to eradicate influenza, the KCHD’s plan provides a comprehensive methodology for educating and informing the public about the prevention/control of influenza in Kent County. This plan was developed as a tool for guiding individual and community actions in order to reduce the risk of influenza.