County of Marin Health and Human Services

Influenza Surveillance Update - Week Ending October 3, 2020


Influenza season is here. Data on influenza testing and influenza-like illness will be posted to this site approximately monthly. This year, Marin County is monitoring respiratory illness activity to indicate potential surges in COVID-19 activity, as well as influenza activity. You can find additional information about respiratory illness and COVID-19 in Marin County here. The best way to protect yourself and others from influenza is to get the flu vaccine. You can find out where to receive the flu vaccine here.

Influenza-like illness activity 

Influenza-like illness (ILI) activity in Marin County is within the expected range for this time of year. ILI surveillance may Emergency department census data from Kaiser San Rafael, MarinHealth, and Novato Community Hospital showed the percentage of visits associated with ILI was 5.1% during week 40 (Sep.27 - Oct.3). See Figure 1 below.

Figure 1. Proportion of Visits due to Influenza-Like Illness (ILI):  Kaiser San Rafael, MarinHealth Medical Center, and Novato Community Hospital Emergency Departments, 2018-2019, 2019-2020, and 2020-2021 Influenza Seasons



Influenza testing 

During week 40 (Sep.27 - Oct.3),  0 (0%) of the 8 specimens tested for influenza were positive. During this influenza season through October 3, 0 specimens have tested positive for influenza. See Figure 2 below. 

Figure 2. Influenza Tests in Marin County, 2020-2021 Influenza Season


Respiratory Illness Data

Marin County is monitoring respiratory illness data for surges that may be related to COVID-19 or influenza. The graph below shows data on respiratory illness admissions to the emergency department over the last three years. See Figure 3 below.

Figure 3. Respiratory illness admissions to the emergency department

ed_update_daily_new.pngInfluenza Related Deaths 

There have been no influenza-related deaths of older adults (>65 years old) in Marin County during the 2020-2021 flu season.

Note: Marin County now includes number of influenza-related deaths in our influenza communications. This does not indicate an increase in deaths compared to previous flu seasons, but a change in reporting procedures.


Visit the California Department of Public Health’s influenza website here for more information.

United States

National influenza activity was minimal during week 39 (Sep.20-26) 
For additional national influenza data, visit the Center for Disease Control and Prevention's influenza surveillance website here.


California Department of Public Health. is external). Accessed 10/6/20.

Centers for Disease Control and Prevention. is external). Accessed 10/6/20.

If you have any questions or comments please contact:
Lisa Santora, MD
Deputy Public Health Officer
(415) 473-4163

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