County of Marin Health and Human Services

Influenza Surveillance Update - Week Ending October 12, 2019


Influenza season is here, and influenza-like illness activity is on the rise in Marin. Positive tests began to increase in September this year, and are currently at expected levels for this time of year.

Influenza-like illness activity 

Flu activity is within expected levels for this time of year. 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  5.4% during week 41 (Oct. 6-12). See Figure 1 below. 

Figure 1. Proportion of Visits due to Influenza-Like Illness (ILI):  Kaiser San Rafael, MGH, and NCH Emergency Departments, 2017-2018, 2018-2019, and 2019-2020 Influenza Seasons


Influenza testing

During week week 41 (Oct. 6-12), 1 (1.9%) of the 54 specimens tested for influenza were positive.  During this influenza season through October 12, 2 specimens have tested positive for influenza. See Figure 2 below. 

Figure 2. Influenza Tests in Marin County, 2019-2020 Influenza Season

Visit for influenza vaccination, testing, and treatment recommendations.


The geographic spread of influenza activity in California is sporadic for week 41 (Oct. 6-12).
Outpatient influenza-like illness and hospitalizations were within expected levels.
Visit the California Department of Public Health’s influenza website for more information.  

United States

Influenza activity was minimal during week 41 (Oct. 6-12).
For additional national influenza data, visit the Center for Disease Control and Prevention's influenza surveillance website.

If you have any questions or comments please contact:
Lisa Santora, MD
Deputy Public 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.


California Department of Public Health. Accessed 10/21/19.

Centers for Disease Control and Prevention. Accessed 10/21/19.


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