Weekly Flu Report, April 15, 2022

Massachusetts Department of Public Health weekly influenza update

Table of Contents

This week’s report


  • Influenza severity for Massachusetts is moderate this week.
  • The percent of influenza-like illness (ILI) visits in Massachusetts is 2.59%, which is higher than the regional baseline of 2.0%.
  • The percent of hospitalizations associated with influenza is 0.97%, which is higher than last season and the 2019-2020 season, but lower than the 2018-2019 season.
  • Overall ILI activity is moderate. The West region is reporting high ILI activity; the Central, Northeast and Southeast regions are reporting moderate ILI activity; Boston, Inner Metro Boston and Outer Metro Boston regions are reporting low ILI activity.
  • Laboratory-confirmed influenza cases increased by 44% this week. More influenza A than influenza B positive specimens have been reported by hospitals and outpatient facilities in Massachusetts. Over 1800 positive labs for influenza were reported this week, which is the highest weekly number reported all season causing the second peak of influenza A in Massachusetts, see figure 5. For influenza A, the predominant strain is currently H3N2.
  • The number of influenza vaccine doses administered this flu season is comparable to last season in the same week. The vaccination rate for all ages is 48%. See figure 6 and 7 for vaccination data.
  • Nationally, influenza activity increased this week. Influenza activity is highest in the central and south-central regions of the country and is increasing in most regions.
  • Additional statewide and national data including geographic spread, ILI activity, and pneumonia and influenza mortality are available at CDC’s FluView Weekly Report at www.cdc.gov/flu/weekly and FluView Interactive www.cdc.gov/flu/weekly/fluviewinteractive.htm.
  • Statewide and national COVID data are available at

It’s not too late to get vaccinated. Flu vaccination is always the best way to prevent flu and its potentially serious complications.

Additional Resources

Date published: April 15, 2022

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