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 2020-2021 Flu/RSV season began on September 27, 2020 and will end on September 25, 2021.

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 May 5, 2021, and may change as more reports are received. 

How widespread is the flu in Arizona right now?

flu activity level in maricopa county is local

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

What does flu look like in Maricopa County hospitals?

The graph below shows the percent of Inpatient and Emergency Department visits that are related to influenza like illness from 34 hospitals across Maricopa County.

chart of influenza-like illness reported in Maricopa County hospitals

Learn More

Help Track Flu

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More Info: 
Flu Near You on Science Friday