County of Marin Health and Human Services

Influenza Surveillance Update, January 2019


Influenza-like illness activity has increased in Marin.  Few laboratory tests were positive in November and early December, however positive tests have increased since mid-December.

Influenza-like illness activity 

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) has increased to moderate levels in December and at expected levels for this time of year.  

Influenza testing

During week 1 (December 30 - January 5), 32 (24.2%) of the 132 specimens tested for influenza were positive.  Of the positive specimens from week 52, 30 (93.8%) were influenza A and 2 (6.3%) were influenza B. During this influenza season through January 5, 96 specimens have tested positive for influenza.  See Figure 1 below. 


Figure 1. 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 widespread during the week 1 (December 30 - January 5).
Outpatient influenza-like illness and hospitalizations were above expected levels.
Visit the California Department of Public Health’s influenza website for more information.  

United States

Influenza activity increased nationally during week 1 (December 30-January 5).
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. h 01/11/2019.

Centers for Disease Control and Prevention. Accessed 01/11/2019.

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