Influenza Surveillance and 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.

 

This Week's Flu Update

 

 

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.

 

 

Year
                       

MMWR
Week
                        

Week
Beginning
                                      

Week
Ending 
                                       

Influenza Activity
Classification*
                                      
2018 1 December 31, 2017 January 6, 2018 Widespread
2017 52 December 24, 2017  December 30, 2017  Widespread
2017 51 December 17, 2017  December 23, 2017 Widespread
2017 50 December 10, 2017 December 16, 2017 Widespread
2017  49 December 3, 2017  December 9, 2017 Widespread
 2017  48 November 26, 2017   December 2, 2017 Regional
 2017   47 November 19, 2017  November 25, 2017 Regional 
 2017  46 November 12, 2017  November 18, 2017  Local 
 2017  45 November 5, 2017  November 11, 2017   Local
 2017  44  October 29, 2017 November 4, 2017   Local
 2017  43 October 22, 2017 October 28, 2017  Local
2017
 42
October 15, 2017
October 21, 2017
Sporadic
2017
 41
October 8, 2017
October 14, 2017
Sporadic
2017
 40
October 1, 2017
October 7, 2017
Sporadic

 

 

  

Connecticut Annual Summaries



National Statistics

 

Weekly national updates are available from the Centers for Disease Control and Prevention's (CDC) FluView website Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window.



International Statistics

 


Connecticut's Influenza Surveillance Systems

  • Hospital Emergency Department Syndromic Surveillance (HEDSS). This system receives daily electronic reports on emergency department visits from more than half of Connecticut's acute care hospitals. Data include a listing of total patient visits with information on their chief complaint, including fever/flu.
  • 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 or sore throat in the absence of a known cause, and the presence of a fever greater than 100 degrees Fahrenheit.
  • Hospital Admissions Syndromic Surveillance (HASS). This system receives daily electronic reports from all 32 acute care hospitals in Connecticut. Information on unscheduled admissions, including those for pneumonia that may be associated with influenza infections, is submitted.
  • Influenza-associated Hospitalizations. In Connecticut, influenza-associated hospitalizations and deaths are reportable to the DPH. Data collected describe the more serious illnesses associated with influenza infections.
  • Laboratory Surveillance. Positive influenza tests are laboratory reportable findings in Connecticut. The DPH tracks these results to determine what types, subtypes, and strains are circulating.

Influenza Activity Classification Definitions*

 

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.