Influenza (Flu) Data

  • Purpose: To understand when and where influenza activity is occurring, to monitor influenza-related illness, outbreaks, hospitalizations, and deaths, and to determine circulating and emerging influenza virus strains.
  • Key Information: Geographic spread and activity level of influenza in the state, laboratory test results, and influenza-related hospitalizations and deaths. Influenza-like-illness (ILI) is defined as patients with a fever over 100°F with cough and/or sore throat (unless there is a known cause other than the flu).
  • Collection Period: Data is collected and analyzed weekly. The active flu season runs yearly from October to May, although data sources are monitored year-round.
  • How data are collected: Rhode Island maintains a robust, multipart system that provides a comprehensive picture of influenza statewide. Specific components of the surveillance system are detailed beneath the following graphs. 
  • Learn more about:

Rhode Island Numbers

Related Health Topics

Notes: This graph displays the percent of all outpatient visits due to influenza-like illness, or %ILI. ILI is defined as a fever AND either a cough or a sore throat, independent of any laboratory testing. Information on outpatient visits to health care providers for ILI is collected through the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet). In Rhode Island, thare are 21 community sentinel providers who participate in ILINet: urgent cares, family practices, pediatricians, university health services, and CVS MinuteClinics. In addition, data from 10 emergency departments are incorporated into ILINet.

Notes:This graph displays the perecent ILI, comparing data from RI, the New England States (HHS Region 1), and the United States as a whole. Data Source: ILINet (See Graph 1 notes for details on ILINet)

Notes: This graph displays the number of individuals who tested positive for influenza and were hospitalized as inpatients in all 10 of Rhode Island's acute care hospitals. These counts are broken down by week and compare multiple flu seasons. All hospitals submit weekly positive flu test data to RIDOH, including age and hospitalization status.

Notes: This graph displays the number of individuals who tested positive for influenza and were hospitalized as inpatients in all 10 of Rhode Island's acute care hospitals, stratified by age group. All hospitals submit weekly positive flu test data to RIDOH, including age and hospitalization status.

Notes: This graph displays the number of positive influenza tests resulted at the Rhode Island State Health Laboratories by week and strain of influenza. Specimens are submitted to RISHL by Providence Community Health Centers, ILINet sentinels, and congregate living facilities experiencing outbreaks. Influenza A subtyping and influenza B lineage testing is performed on many of the specimens to monitor circulating influenza strains and to assist CDC in identifying novel viruses.

Influenza-Associated Deaths*

Notes: *Defined as a death resulting from a clinically compatible illness that was confirmed to be influenza by an appropriate laboratory or rapid diagnostic test. There should be no period of complete recovery between the illness and death.