Influenza Surveillance Systems

The Connecticut Department of Public Health (DPH) uses multiple surveillance systems to monitor circulating influenza viruses. These surveillance systems allow the DPH to get an idea about the strain of influenza viruses that are causing illness in the state, outbreaks of influenza in healthcare centers; and illnesses, hospitalizations and deaths associated due to influenza.

The EpiCenter System: This system receives near real-time reports on ED visits from all 38 licensed, hospital emergency departments in Connecticut. Data include a description of the chief complaint, or reason for visit, including fever/flu. The EpiCenter system replaced the Hospital Emergency Department Syndromic Surveillance system (HEDSS) for the 2018-2019 season. Caution should be used when comparing EpiCenter surveillance data to historical HEDSS data.

Sentinel Provider Surveillance:  The percentage of patient visits for ILI is reported to the DPH on a weekly basis by a statewide network of volunteer outpatient providers known as ILINet. ILI is defined as a cough and/or sore throat and the presence of a fever >100o F without a known cause other than influenza. 

Influenza-associated Hospitalizations and/or Deaths: Providers are required to report influenza-associated hospitalizations and influenza-associated deaths. Data collected describe the more serious illnesses associated with influenza infections.

Laboratory Surveillance: In Connecticut, positive influenza results are reportable by the laboratory conducting the test. Rapid antigen results are only reportable by laboratories with electronic file reporting. These results are used to determine what types, subtypes, and strains are circulating.

This page last updated 9/30/2019.