Reporting Guidelines

The major objectives of influenza surveillance this season are to describe risk factors for and burden of severe illness, provide information for management of situations requiring public health intervention(s) (e.g., prophylaxis in a congregate care facility), identify changes in the severity and epidemiology of influenza, and identify novel strains.
For influenza reporting, I-NEDSS contains three different case-based modules: novel influenza, pediatric influenza-associated deaths, and influenza-associated ICU hospitalization. Please enter cases into the appropriate module. For female patients in the ICU, enter important information on pregnancy/postpartum status. If updated information for any patient becomes available after the initial report (e.g., results of a PCR test, death), please update the I-NEDSS report. Providers should report the following to CDPH:  
  1. Suspected novel influenza (e.g., severe respiratory illness of unknown etiology associated with recent international travel, contact with swine, or any case of human infection with an influenza A virus that is different from currently circulating human influenza H1 and H3 viruses). Suspected Novel Influenza cases are reportable immediately, within three hours. Note: For surveillance purposes, 2009 H1N1 (A) influenza is no longer considered to be a novel influenza strain. 
  2.  Pediatric influenza-associated death is defined as death of an individual < 18 years of age resulting from a clinically compatible illness confirmed to be influenza by culture, PCR, commercial rapid influenza, or other appropriate diagnostic test. These cases are reportable as soon as possible, but within seven days. 
  3.  Influenza associated Intensive Care Unit (ICU) hospitalizations are defined as individuals hospitalized in an ICU with a positive laboratory test for influenza A or B, including specimens identified as influenza A/H3N2, A/H1N1pdm09, and specimens not subtyped (e.g., influenza positive cases by PCR or any rapid test such as EIA). These cases are reportable as soon as possible, but within 24 hours.
  4.  Outbreaks of influenza or influenza-like illness in a congregate setting (e.g., correctional or long-term care facility): Additional information regarding reporting of outbreaks of influenza and influenza-like illness in congregate settings can be found here.  
For more information about reporting: IDPH Influenza Testing and Reporting Guidelines.

testing Guidelines

Influenza testing at the IDPH Laboratory is performed on a case-by-case basis and must be approved by CDPH prior to submitting specimens.  If approved, an authorization code will be provided that will authorize influenza testing at the IDPH Laboratory.  Specimens submitted to IDPH Laboratory without prior approval will be rejected and stored until further information is obtained.  To request authorization:
  1. Call 312-743-9000 and press 1 when prompted. If no answer, leave a voicemail with a contact name and a call-back number. 
  2. When contacted by CDPH, please have the patient information readily available and the reason why influenza testing is being requested at the IDPH Laboratory. If approved, an authorization code will be provided during the call.  
  3. Once approved, the provider must submit the test order electronically using the IDPH Electronic Test Ordering and Reporting (ETOR) portal. To enroll email 
  4. The submitter must arrange for the specimen to be transported to the IDPH Laboratory. All specimens must be received at the IDPH Laboratory for testing within three days of specimen collection except if frozen. 
  5. Specimen results will be communicated to the submitter as reported in the ETOR portal.
For more information about reporting: IDPH Influenza Testing and Reporting Guidelines.

Novel and Variant Influenza

IDPH SIREN, Variant and Novel Influenza Awareness - June 2023
To notify CDPH of any suspect novel or variant influenza cases in Chicago residents and request influenza RT-PCR testing, call 312-743-9000 and press 1 when prompted. After hours, call 311 and ask to speak with the physician on-call.

Additionally, CDC is requesting that during the late spring and summer months, influenza A positive samples from patients in the ICU that are not subtyped in clinical labs be submitted to state or local public health laboratories for subtyping. Call CDPH at 312-743-9000 ext 1 during business hours to arrange for specimen submission to the IDPH Public Health Laboratory if your patient meets this criteria.

Avian Influenza A Viruses
Avian influenza A viruses do not normally infect humans, but sporadic human infections have occurred. Illness in humans caused by avian influenza A virus infections has ranged from mild to severe (e.g. pneumonia). Several subtypes of avian influenza A viruses are known to have infected people (H5, H6, H7, H9, H10 viruses). Highly pathogenic Asian avian influenza A(H5N1) and low pathogenic Asian A(H7N9) viruses account for the majority of human infections with avian influenza A viruses. More information about specific novel influenza A viruses, including those that have caused illness in humans, is available here.

Highly pathogenic avian influenza (HPAI) A(H5N1) viruses have been detected in U.S. wild birds, commercial poultry, and backyard flocks beginning in January 2022. CDC considers the current risk to the general public’s health in the U.S. to be low. However, because the recently detected HPAI A(H5N1) viruses are related to viruses that have caused severe disease in infected humans, they should be regarded as having the potential to cause severe disease in humans until shown otherwise. For more information visit the CDC Avian Influenza Current Situation Summary.

Clinicians should consider the following for surveillance and testing:
  • Consider the possibility of infection with novel influenza A viruses with the potential to cause severe disease in humans in patients who present with influenza-like illness (ILI) or acute respiratory infection (ARI) symptoms and who have had recent direct or close contact (particularly unprotected exposure, e.g., without use of respiratory protection and eye protection)*  <10 days prior to illness onset to the following birds with known or suspected avian influenza A virus infection:
    • Domestic poultry (e.g., sick or dead chickens or turkeys)
    • Captive birds of prey (e.g., sick, dead, or well-appearing falcons that have had contact with wild aquatic birds)
    • Wild aquatic birds (e.g., sick, dead, or well-appearing ducks, geese, swans).
  • If infection with a novel influenza A virus with the potential to cause severe disease in humans is suspected, respiratory specimens should be collected while following recommended infection control precautions. Notify CDPH as soon as possible by calling 312-743-9000 and press 1 when prompted. After hours, call 311 and ask to speak with the physician on-call. We will work with you to submit specimens to the IDPH public health laboratory for testing. 
  • Suspected cases of novel influenza should be reported in I-NEDSS immediately and should not wait until results have been returned.
*Exposure, especially unprotected exposure (e.g., without use of respiratory protection and eye protection) may include: direct contact with birds (e.g., handling, slaughtering, defeathering, butchering, preparation for consumption); or direct contact with surfaces contaminated with feces or bird parts (carcasses, internal organs, etc.); or prolonged close exposure to birds.

For more information see: Brief Summary for Clinicians: Evaluating and Managing Patients Exposed to Birds Infected with Avian Influenza A Viruses of Public Health Concern. This document briefly summarizes important clinical information related to avian influenza A viruses of public health concern and recommendations for patient evaluation, treatment, and testing along with links to interim guidance on: 
Variant Influenza
Influenza A viruses circulating in pigs that have infected humans are referred to as “variant” viruses and denoted with a letter “v”. Human infections with H1N1v, H3N2v and H1N2v viruses have been detected in the United States.

Variant virus infection cannot be distinguished by clinical features from seasonal influenza virus infection or from infection with other respiratory viruses that can cause influenza-like illness. Therefore, the key to suspecting variant virus infection in an ill patient is to elicit an epidemiological link to recent swine exposure in the week prior to illness onset. Exposure can be defined as follows:
  • Direct contact with swine (e.g., showing swine, raising swine, feeding swine, or cleaning swine waste)
  • Indirect exposure to swine (e.g., visiting a swine farm or walking through a swine barn), especially if swine were known to be ill; or
  • Close contact (within 2 meters or approximately 6 feet) with an ill person who had recent swine exposure or is known to be infected with a variant virus.
For any ill person with an exposure as defined above, respiratory samples should be taken for testing. Contact CDPH as soon as possible by calling 312-743-9000 and press 1 when prompted. After hours, call 311 and ask to speak with the physician on-call. We will help arrange for appropriate testing of clinical specimens at the IDPH public health laboratory. Suspected cases of variant influenza should be reported in I-NEDSS immediately and should not wait until results have been returned.

For more guidance on variant influenza infections in humans including clinical management and infection prevention see: Interim Guidance for Clinicians on Human Infections with Variant Influenza Viruses

Weekly Surveillance Report

The Chicago Flu Update is now available online.
Visit for the current report. Reports are published weekly on Friday. 

Archived reports are available here.

Influenza Reporting

For Clinical Questions Contact:

The CDPH Disease Reporting Hotline at 312-743-9000

*After hours, weekends, and holidays, call 311 and ask for the communicable disease physician on-call (or 312-744-5000 if outside the City of Chicago)

Schools:  please click here for reporting and management

Reporting Guidelines: 
Please refer to the relevant section in the left portion of this page.

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