DPH: Influenza Surveillance and Statistics

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*
                                      
2017
April 30, 2017
May 6, 2017
Regional
2017
April 23, 2017
April 29, 2017
Widespread
2017
April 16, 2017
April 22, 2017
Widespread
2017
April 9, 2017
April 15, 2017
Widespread
2017
April 2, 2017
April 8, 2017
Widespread
2017
March 26, 2017
April 1, 2017
Widespread
2017
March 19, 2017
March 25, 2017
Widespread
2017
March 12, 2017
March 18, 2017
Widespread
2017
March 5, 2017
March 11, 2017
Widespread
2017
February 26, 2017
March 4, 2017
Widespread
2017
February 19, 2017
February 25, 2017
Widespread
2017
February 12, 2017
February 18, 2017
Widespread
2017
February 5, 2017
February 11, 2017
Widespread
2017
January 29, 2017
February 4, 2017
Widespread
2017
January 22, 2017
January 28, 2017
Widespread
2017
January 15, 2017
January 21, 2017
Widespread
2017
January 8, 2017
January 14, 2017
Widespread
2017
January 1, 2017
January 7, 2017
Widespread
2016
December 25, 2016
December 31, 2016
Widespread
2016
December 18, 2016
December 24, 2016
Regional
2016
December 11, 2016
December 17, 2016
Regional
2016
December 4, 2016
December 10, 2016
Local
2016
November 27, 2016
December 3, 2016
Local
2016
November 20, 2016
November 26, 2016
Local
2016
November 13, 2016
November 19, 2016
Local
2016
November 6, 2016
November 12, 2016
Sporadic
2016
October 30, 2016
November 5, 2016
Sporadic
2016
October 23, 2016
October 29, 2016
Sporadic
2016
October 16, 2016
October 22, 2016
Sporadic
201641October 9, 2016October 15, 2016Sporadic
201640October 2, 2016October 8, 2016Sporadic



  

Connecticut Annual Summaries



National Statistics

 

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



International Statistics

International influenza activity is available at the World Health Organization website.

 


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.

*Reporting of influenza-like illness (ILI) is conducted through a statewide network of volunteer outpatient providers known as ILINet.

^Recent is defined as within 2 weeks.

#In general, counties within Connecticut are identified as regions for general data collection and dissemination. The state is also broken down into 5 planning regions by the Division of Emergency Management and Homeland Security (DEMHS). These regions are used by the DPH for influenza surveillance in the event of a novel flu outbreak.
















To contact the Epidemiology and Emerging Infections Program, please call 860-509-7994.





Content Last Modified on 5/11/2017 9:15:59 AM