Connecticut Seasonal Influenza Statistics
In Connecticut, the Department of Public Health uses multiple systems to monitor circulating influenza viruses. During the influenza season, weekly flu updates are posted from October of the current year, through May of the following year. Annual summaries are also posted for comparison. The national flu picture may vary from what we are seeing on a state level.
Current Influenza Season Weekly Updates
To see how this year's influenza season has progressed, please click on the MMWR Week number that corresponds with the week's beginning and end date you are interested in seeing. Each report is progressive and includes data starting from the beginning of this flu season.
All data are preliminary and subject to change.
|2019||20||May 12, 2019||May 18, 2019||Local|
|2019||19||May 5, 2019||May 11, 2019||Regional|
|2019||18||April 28, 2019||May 4, 2019||Regional|
|2019||17||April 21, 2019||April 27, 2019||Widespread|
|2019||16||April 14, 2019||April 20, 2019||Widespread|
|2019||15||April 7, 2019||April 13, 2019||Widespread|
|2019||14||March 31, 2019||April 6, 2019||Widespread|
|2019||13||March 24, 2019||March 30, 2019||Widespread|
|2019||12||March 17, 2019||March 23, 2019||Widespread|
|2019||11||March 10, 2019||March 16, 2019||Widespread|
|2019||10||March 3, 2019||March 9, 2019||Widespread|
|2019||9||February 24, 2019||March 2, 2019||Widespread|
|2019||8||February 17, 2019||February 23, 2019||Widespread|
|2019||7||February 10, 2019||February 16, 2019||Widespread|
|2019||6||February 3, 2019||February 9, 2019||Widespread|
|2019||5||January 27, 2019||February 2, 2019||Widespread|
|2019||4||January 20, 2019||January 26, 2019||Widespread|
|2019||3||January 13, 2019||January 19, 2019||Widespread|
|2019||2||January 6, 2019||January 12, 2019||Widespread|
|2019||1||December 30, 2018||January 5, 2019||Widespread|
|2018||52||December 23, 2018||December 29, 2018||Widespread|
|2018||51||December 16, 2018||December 22, 2018||Widespread|
|2018||50||December 9, 2018||December 15, 2018||Regional|
|2018||49||December 2, 2018||December 8, 2018||Regional|
|2018||48||November 25, 2018||December 1, 2018||Regional|
|2018||47||November 18, 2018||November 24, 2018||Regional|
|2018||46||November 11, 2018||November 17, 2018||Local|
|2018||45||November 4, 2018||November 10, 2018||Local|
|2018||44||October 28, 2018||November 3, 2018||Local|
|2018||43||October 21, 2018||October 27, 2018||Sporadic|
|2018||42||October 14, 2018||October 20, 2018||Sporadic|
October 7, 2018
October 13, 2018
Connecticut Annual Summaries
Weekly national updates are available from the Centers for Disease Control and Prevention's (CDC) FluView website.
FluView Interactive (requires adobe flashplayer)
International influenza activity is available at the World Health Organization website.
Connecticut's Influenza Surveillance Systems
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). During 2017-2018, 18 additional emergency department facilities began sending data to the EpiCenter, and caution should be used when comparing EpiCenter surveillance data to historical HEDSS data.
Sentinel Provider Surveillance: Reporting of influenza-like illness (ILI) is conducted through a statewide network of volunteer outpatient providers known as ILINet. The proportion of patients exhibiting ILI is reported to the DPH on a weekly basis. ILI is defined as a cough and/or sore throat in the absence of a known cause, and the presence of a fever >100o F.
Influenza-associated Hospitalizations and/or Deaths: Providers are required to report influenza-associated hospitalizations and influenza-associated deaths, they are not required to report any positive influenza test results. 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.
|No Activity||No laboratory-confirmed cases AND no increase in the number of cases of ILI.|
|Sporadic Activity||Small numbers of lab-confirmed cases OR lab confirmed outbreak in one institution, but NO increase in cases of ILI.|
|Local Activity||Outbreaks of influenza or increases in ILI cases AND recent laboratory-confirmed influenza in a single region of the state.|
|Regional Activity||Outbreaks of influenza or increases in ILI cases AND recent laboratory-confirmed influenza in at least 2 but less than half of the regions of the state with recent laboratory evidence of influenza in those regions.|
|Widespread Activity||Outbreaks of influenza OR increases in ILI cases AND recent laboratory-confirmed influenza in at least half the regions of the state with recent laboratory evidence of influenza in the state.|
To contact the Epidemiology and Emerging Infections Program, please call 860-509-7994.