Communicable Disease

Monitoring Influenza in Kent County

In General

Influenza causes an average of 36,000 deaths/year in the United States (1990-99). 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 97 deaths in 2006 from influenza or pneumonia; 84.5% of these deaths occurred in the 75 years of age and older population. Influenza/pneumonia was the 7th most common cause of death in Kent County in 2006.

Last Year

In Kent County, the 2006-07 influenza season peaked during the second week of February. This peak correlated with National laboratory influenza data that also demonstrated a peak during the second week of February. The Health Department received 130 case reports of laboratory confirmed influenza which was significantly smaller than the number of reports received the previous year (769 cases in 2005-06). Despite the decrease in cases reported, the data still proved to be an accurate indicator of the seasonal peak. Schools and daycare centers reported 21,917 cases of respiratory flu and 26,582 cases of “unknown” flu.

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. Provide information regarding the emergence of a new influenza strain
  4. 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 - Influenza is also a state mandated reportable disease. 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

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.accessKent.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.