About This Year's Flu

What Public Health Tracks

Public Health tracks cases of influenza (flu) and respiratory syncytial virus (RSV). The team that tracks these cases creates weekly reports during the influenza/RSV season. At the end of the year, a yearly report summarizes the data. 

The 2019-2020 Flu/RSV Season began on September 29, 2019 and will end on September 26, 2020.

Public Health tracks flu and RSV cases by MMWR weeks, which is a standard way across the United States of numbering weeks in a year to track disease. (Learn more about MMWR weeks .) Weekly reports start on Sunday and end the following Saturday.

This Week's Flu Report

All data are preliminary as of November 6, 2019, and may change as more reports are received.

How widespread is the flu in Arizona right now?

flu activity level

See definitions >

How do this season's current numbers compare to previous years' data?

flu case counts table

How does flu in Maricopa County this year compare to flu in previous years?

flu case frequency chart by week and past seasons

Learn More

Help Track Flu

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More Info: 
Flu Near You on Science Friday