Issue 4 - May 12, 2019 - May 18, 2019 
Influenza activity in Marin County
The Marin County Department of Health and Human Services conducts local influenza surveillance during flu season each year and offers periodic updates to you, our healthcare providers. 
Local influenza activity has declined significantly, consistent with the usual late spring resolution of flu season. This is the final influenza surveillance report for the 2018/19 season. Surveillance reports will resume in Fall 2019. For additional information about influenza activity in Marin County, visit

During the third week of May, influenza-like illness activity was at expected levels in Marin County (Figure 1) with 0% positive influenza tests (Figure 2). 
Influenza-like illness activity:  Influenza-like illness activity is at expected levels in Marin County for this time of year, and has been decreasing since April. Discharge data from Kaiser San Rafael, Marin General Hospital, and Novato Community Hospital emergency departments showed the percentage of visits associated with influenza-like illness (ILI) was 6.55% during week 20 (May 12 - May 18). See Figure 1 below. 
Figure 1.  Proportion of Visits due to Influenza-Like Illness (ILI):
Kaiser San Rafael, MGH, and NCH Emergency Departments, 2016-17, 2017-2018, and 2018-2019 Influenza Seasons
Influenza testing: During week 20 (May 12 - May 18), 0 (0%) of the 58 specimens tested for influenza were positive. During this influenza season through May 18, 499 specimens have tested positive for influenza.  See Figure 2 below. 
Figure 2.  Influenza Tests in Marin County, 2018-2019 Influenza Season
Visit for influenza vaccination, testing, and treatment recommendations.


Influenza activity in California was at expected levels during the week of May 12. View full influenza updates at the California Department of Public Health's influenza surveillance website.

United States

National influenza activity has decreased and is at normal levels for this time of year. View more detailed information at the Centers for Disease Control and Prevention's influenza surveillance website.
Copyright ©  2019
Marin County Department of Health and Human Services.
All rights reserved.

Lisa Santora, MD, MPH
Deputy Health Officer
(415) 473-4163

This publication is provided to you by the Office of the Public Health Officer, County of Marin Department of Health and Human Services.

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