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    • This is a Non-Federal dataset covered by different Terms of Use than Data.gov.

    Influenza Risk Level by ZIP Code

    Metadata Updated: April 12, 2026

    This dataset contains the weekly estimated influenza risk level for each ZIP Code in Chicago. Estimates are made during flu season, which goes from MMWR week 40 to week 20 of the following year.

    The risk level is based on observed level of Influenza-Like Illness (ILI). ILI Activity Level is determined as follows: ILI percentage for each ZIP Code for the week is compared to the mean ILI percentage during the non-influenza months (summer months). Level 1 corresponds to an ILI percentage below the mean, level 2 to an ILI percentage less than one standard deviation (SD) above the mean, level 3 to an ILI percentage more than one, but less than two SDs above mean, and so on, with level 10 corresponding to an ILI percentage more than eight SDs above the mean.

    For more information on ESSENCE, which compiles the estimates, see https://www.dph.illinois.gov/data-statistics/syndromic-surveillance

    All data are provisional and subject to change. Information is updated as additional details are received. At any given time, this dataset reflects data currently known to CDPH. Numbers in this dataset may differ from other public sources.

    Access & Use Information

    Public: This dataset is intended for public access and use. Non-Federal: This dataset is covered by different Terms of Use than Data.gov. License: No license information was provided.

    Downloads & Resources

    Dates

    Metadata Created Date November 7, 2021
    Metadata Updated Date April 12, 2026

    Metadata Source

    Harvested from Chicago JSON

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Created Date November 7, 2021
    Metadata Updated Date April 12, 2026
    Publisher data.cityofchicago.org
    Maintainer
    Identifier https://data.cityofchicago.org/api/views/8vvr-jv2g
    Data First Published 2020-10-07
    Data Last Modified 2026-04-11
    Category Health & Human Services
    Public Access Level public
    Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
    Metadata Catalog ID https://data.cityofchicago.org/data.json
    Schema Version https://project-open-data.cio.gov/v1.1/schema
    Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
    Harvest Object Id 055536ca-ae0c-4163-ad68-e1e30aaccd9f
    Harvest Source Id 7590e386-229e-453a-8e53-6f18e200e421
    Harvest Source Title Chicago JSON
    Homepage URL https://data.cityofchicago.org/d/8vvr-jv2g
    Source Datajson Identifier True
    Source Hash f4cfba61a3a2da051f3acd41e63557d65b1e01a810b029d1f3f2cdc45746290c
    Source Schema Version 1.1

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