Influenza is a contagious infection of the nose, throat and lungs caused by a virus. The flu is generally spread to others when an infected person coughs or sneezes. Flu symptoms include:

  • cough
  • fever
  • chills
  • sore throat
  • muscle or body aches
  • runny or stuffy nose
  • headache
  • fatigue.

The flu vaccine is the best way to protect against the flu. The flu vaccine causes antibodies to develop in the body approximately two weeks after vaccination. These antibodies provide protection against infection when the viruses are circulating. The flu vaccine can protect against influenza and its potentially serious complications. Vaccination of high-risk persons is especially important to decrease their risk of severe flu illness. Getting vaccinated not only protects you, but also prevents you from spreading the disease to your family, friends, and co-workers.

The CDC recommends everyone 6 months and older should receive the flu vaccine each year. The typical influenza season lasts from August to May.

More seasonal influenza information can be found here.

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Influenza Vaccine Data Visualization

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2022 Data Summary: 2022-2023 Influenza Vaccine Data Summary  

On 5/14/2024, census population estimates for 2021 and 2022 were updated on the Iowa Public Health Tracking Portal. Previously, only 2020 census population estimates were available and used for 2021-2023 immunization coverage data. Due to the updated census population estimates, immunization rates for 2021-2023 data using the census population denominator have changed from what was previously reported on the portal. This change better reflects the true immunization rate using census denominators.

Seasonal influenza vaccination data in Iowa is based on doses reported to the Iowa Immunization Registry Information System (IRIS) for Iowans. IRIS is a confidential, computerized, population-based system that tracks immunization for children, adolescents and adults who are seen at public and private healthcare provider sites throughout the state of Iowa. The data for the current influenza season is updated weekly and there may be a lag between the vaccine administration date and the date reported to IRIS. Seasonal influenza vaccination data are updated as more information is reported to IRIS.

Measure Description:

  • Persons Receiving Flu Vaccine: The number of Iowa residents recorded in IRIS as having received at least one dose of influenza vaccine during the specified flu season.
  • Percent of Population Receiving Flu Vaccine: The number of Iowa residents recorded in IRIS as having received at least one dose of influenza vaccine divided by the Iowa population estimates or county population during the specified flu season.

Data Notes:

  • Influenza data related to percent of the population receiving flu vaccine uses the assumption a dose of vaccine equates a single person.
  • Influenza data is updated weekly and is based upon doses of vaccine reported to IRIS.
  • Influenza data for the 2016-2017 and 2017-2018 seasons were updated to include only Iowa residents during the February 2020 release. County-level influenza data were unaffected by this change.
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