County of Marin Health and Human Services

Influenza Surveillance Update - Week Ending May 18, 2019


Influenza-like illness activity has decreased in Marin.  Positive tests have continued to decline since April 2019.

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 6.55% during week 20 (May 12-18). 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.


The geographic spread of influenza activity in California is normal for week 20 (May 12 - May 18).
Outpatient influenza-like illness and hospitalizations were at expected levels.
Visit the California Department of Public Health’s influenza website for more information.  

United States

Influenza activity was normal during week 20 (May 12 - May 18).
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 5/23/19.

Centers for Disease Control and Prevention. Accessed 5/23/19.

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