Are you prepared for the next flu season?: Lessons learned from Nebraska influenza-like illness hospital admission survey

Influenza is a leading public health threat, but is preventable. Surveillance of influenza activity allows public health to focus infection control and prevention measures. This study described influenza activity in Nebraska during the last four influenza seasons from fall 2004 to spring 2008 with the influenza-like illness (ILI) hospital admission survey data.

Nebraska Department of Health and Human Services (NDHHS) collected information on ILI hospital admissions from hospitals across the state on a weekly basis, from the first week of November to the last week of March in the next year. Data were compiled in Excel. ILI hospital admission rates were tracked over time and compared among different influenza seasons, age groups, and local health departments.

In Nebraska, the peak of influenza activity usually came in February. The 2007-2008 influenza season was the most severe in the last four years. Children under the age of 5 and seniors over 65 years old were vulnerable to influenza, and had higher hospitalization rate than the rest of the community. County population size did not appeared to associate with ILI hospital admission rate.

ILI hospital admission survey provides valuable information on influenza epidemic; however, it only represents the severe cases of influenza victims who required hospitalization. Future improvements to the ILI hospital admission survey can be combining ILI hospital admission data with other surveillance systems, such as laboratory and sentinel provider surveillance, extending the survey to include ILI emergency room visits, and breaking down age groups to more specific and meaningful categories.