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. 

For each week, the report covers:

  • How many new cases were identified
  • Total number of cases for the flu season
  • What strain of flu those cases were (if known)
  • How many pediatric deaths there were (if applicable)
  • Other details that help identify what strains are common, how severe the season is, and if the number of cases is increasing, decreasing, or staying level

The first day of the 2018-2019 season was September 30, 2018. Flu/RSV season will continue through September 28, 2019.

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

Data below is as of December 1, 2018.

All data are preliminary and may change as more reports are received.

How widespread is the flu right now?

weekly status of activity level in arizona

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

weekly table with case counts

How does flu in Maricopa County compare this year to the previous five season average?

weekly comparison chart