Novel Coronavirus (COVID-19) Surveillance Update

Marin County Public Health tracks demographic, geographic, and clinical information about confirmed COVID-19 cases to inform the COVID-19 response and understand factors associated with COVID-19 transmission and clinical outcomes in our community. We are consistently improving our data collection, analysis, and sharing procedures, so will continue to add additional indicators to this report as data become available. In this report, you will find data for the following key indicators related to confirmed COVID-19 cases and testing:

* There are two main indicators of potential COVID-19 activity locally— the number of confirmed cases and the general number of people experiencing severe respiratory illness. Seeing important increases helps our healthcare providers and partners know when COVID-19 activity may be increasing in Marin. Marin County Public Health receives regular updates on cases of respiratory illness from all Marin County emergency departments (ED), and from Emergency Medical Services (EMS), our countywide 911 ambulance response system. We track these over time, and compare to prior years. Note there’s always ups and downs in our usual activity, and we’re looking for significant changes.

Information about confirmed cases is updated daily by approximately 5pm Pacific Standard Time (PST). Information about respiratory illness activity is updated biweekly each Tuesday and Friday. Data are provisional and subject to change.

Today's Updates

The information gives us a snapshot of what COVID-19 looks like in Marin County today. "Newly reported" are changes in the total number of cases, hospitalizations ,and deaths reported on this surveillance website since yesterday. "Current COVID+ Hospitalizations" are the number of patients currently in Marin Hospitals who have confirmed COVID-19.

 

Cumulative Information

This information shows how COVID-19 has impacted Marin County since the first case.

 

Total Cases, Recovered, Hospitalizations and Deaths by Date Reported

Tracking the cumulative number of COVID-19 cases, hospitalizations, deaths, and modeled estimate of individuals who have recovered* helps us understand how this pandemic has impacted our community over time. The figure below displays the total number of cases, hospitalizations, deaths, and modeled estimate of individuals who have recovered* among Marin County residents by date the information was reported to Marin County Public Health. The first case was reported on March 8, 2020. The charts below are live and interactive, hover over the chart with your cursor to see the total number reported each day and observe the daily increase over time.

 

Total Cases by Geographic Location

Mapping cases by geographic regions helps us view where COVID-19 cases have been diagnosed in our community. The map below shows the number of confirmed COVID-19 cases by six geographic regions in Marin County: San Rafael, Novato, San Anselmo + Fairfax, West Marin, Central Marin, and Southern Marin (only communities with greater than 20,000 population are named separately). Note that the number of confirmed cases in a given community are reflective of testing. This map is live and interactive, click on each jurisdiction to view the number of cases.

 

Daily Trends

 

Daily Newly Reported Cases

This chart shows the number of new COVID positive cases reported daily. Positive cases are reported for Marin County residents only, and prioritized to be reported earlier than negative tests results to assist in contact tracing and investigation. We can therefore show positive cases by report date for recent dates.

Percent Positive Summary

The table below displays the 7-day rolling average of percent positive tests for Marin residents between 2 weeks to 1 week ago. This time period is the most recent reporting period that has updated testing results in the state reporting system, CalREDIE.

Daily COVID-19 Tests Conducted

Due to the high degree of variation in the time needed to complete tests by different labs, there is a delay is this reporting. Total daily tests include all people tested in Marin County regardless whether the test was for Marin County resident a person who lives outside of Marin County.

Daily Hospital and ICU COVID-19 Cases, Marin County

This information helps us understand how COVID-19 is impacting our community as the most severe cases will become hospitalized and may require life-saving care in an Intensive Care Unit (ICU). It also helps inform us about the use of available hospital resources to inform emergency planning for incoming COVID-19 cases. The figure below shows the total number of individuals with COVID-19 who are hospitalized or in an ICU by day in Marin County Hospitals as of April 1, 2020, the earliest date for which data are available. Not all individuals hospitalized with COVID-19 are in the ICU, and the daily number of individuals hospitalized and in the ICU has been less than 10 early April.

 

Demographics

Cases, Hospitalizations, and Deaths by Age, Gender and Race/Ethnicity

Comparing demographic information for confirmed COVID-19 cases to the demographics in our community's population helps inform us about which groups may be more impacted by COVID-19. The figure immediately below to the left displays the number of laboratory confirmed COVID-19 cases, hospitalizations, and deaths by age group compared to the Marin County population as a whole while the figure to the right displays the same information by gender. The pie chart below these figures presents the same information by race/ethnicity. To date, the majority of confirmed cases and hospitalizations have occurred among individuals greater than 50 years of age and all reported deaths have been among those 65 years of age or older. The majority of confirmed cases, hospitalizations, and deaths have occurred among those who are male and of White, non-Hispanic; Hispanic; or Asian, non-Hispanic race/ethnicity.

 

 

Other Indicators of COVID-19 Impacts

In addition to measuring documented cases of COVID-19, we also look at data tracking deaths from any cause (all-cause deaths) and severe respiratory illness to see early signs of how COVID-19 may be affecting Marin County.

 

Weekly Count of All-Cause Deaths in Marin County: Comparing 2018-2019 to 2020

Looking at trends in all-cause deaths may help us to identify if we are seeing fewer or greater number of deaths than usual in Marin County. Seeing a sustained spike in the number of deaths occurring in a given week in 2020 compared to 2018-19 may demonstrate COVID-19's impact on Marin County. The line chart below shows the two-week rolling average of all-cause deaths by week in 2020 as compared to 2018 and 2019 combined. The date on the horizontal axis represents the last day in the two-week rolling average. For example, the two-week rolling average of 36 for the week ending on Apr 25 (representing week of Apr 17-25), means that there 76 deaths recorded in the two week period prior to Apr 26 (Apr 11-25). The number of deaths in recent weeks remain similar to trends seen in prior years.

 

Respiratory Illness Activity

Common symptoms of COVID-19 include fever, cough, and difficulty breathing. Respiratory illness activity will capture visits that may be due to COVID-19 and influenza-like illnesses. The majority of individuals with COVID-19 will experience mild to moderate symptoms. However, some individuals may experience more severe symptoms and require a higher level of medical care through EMS or the ED. Tracking the total number of visits and those due to respiratory illnesses provides a situational awareness of current resource needs in our community. Each daily count below reflects 3-day rolling averages.Figures 1-3 display information on current trends in EMS calls and ED visits due to respiratory illnesses total and by age.

Utilization Trends:Over the past week, the number of ED and EMS visits and those due to respiratory illnesses have been lower than daily averages seen in January-April, 2019. Marin County Public Health will continue to monitor trends to identify any significant changes (Figures 1A-B).

Figures 1A-B:Number of Total Visits and Visits due to Respiratory Illnesses

Total Marin County Emergency Medical Services Calls (1A)

The stacked bar chart below shows the total number of EMS calls and those due to respiratory illnesses based on 3-day rolling averages. Over the past month, EMS calls have been below January to April 2019 averages.

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Total Kaiser San Rafael, MarinHealth Medical Center and Novato Community Hospital Emergency Department Visits* (1B)

The stacked bar chart below shows the total number of Kaiser San Rafael, MarinHealth and Novato Community Hospital ED visits and those due to respiratory illnesses based on 3-day rolling averages. ED visits are notably below January to April 2019 averages and less than half of daily visit levels seen in January and February of this year.

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*Discharge data from Kaiser San Rafael, MarinHealth and Novato Community Hospital show trends in ED visits due to respiratory illnesses and are updated as soon as data are available.

 

 

Percentage of visits due to respiratory illnesses: Approximately 7% of Emergency Medical Services (EMS) calls and 4% of Emergency Department (ED) visits were due to respiratory illnesses (Figures 2A-B).

Figures 2A-B: Daily Proportion of Visits due to Respiratory Illnesses

Percentage of Marin County Emergency Medical Services Calls (2A)

The line chart below shows that the percentage of EMS calls due to respiratory illnesses recently decreased and remains similar to trends observed during this time in 2018 (dotted blue line) and 2019 (dashed black line).

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Percentage of Kaiser San Rafael, MarinHealth Medical Center and Novato Community Hospital Emergency Department Visits* (2B)

The line chart below shows that the percentage of Kaiser San Rafael, MarinHealth, and Novato Community Hospital ED visits due to respiratory illnesses is decreasing and remains similar to trends observed during this time in 2018 (dotted black line) and 2019 (dashed black line).

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*Discharge data from Kaiser San Rafael, MarinHealth and Novato Community Hospital show trends in ED visits due to respiratory illnesses and are updated as soon as data are available.

 

 

Age Distribution of Respiratory Illness Visits: The majority of respiratory illness-related EMS calls occur among those 65 years and older, while the majority of ED visits due to respiratory illnesses occur among those less than 65 years of age (Figures 3A-B).

Figures 3A-B: Total Visits Daily due to Respiratory Illnesses by Age

Total Marin County Emergency Medical Services Calls by Age (3A)

The stacked bar chart below shows the total number of EMS calls due to respiratory illnesses by age categories 0-18 years (blue), 19-64 years (gold), and 65 or more years (red). The majority of EMS calls due to respiratory illnesses occur among those 65 years or older. The total number of respiratory illness EMS calls based on 3-day rolling averages are somewhat below January to April 2019 averages.

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Total Kaiser San Rafael, MarinHealth Medical Center and Novato Community Hospital Emergency Department Visits by Age* (3B)

The stacked bar chart below shows the total number of Kaiser San Rafael, MarinHealth, and Novato Community Hospital ED visits due to respiratory illnesses by age categories 0-18 years (blue), 19-64 years (gold), and 65 or more years (red). The majority of ED visits due to respiratory illnesses occur among those less than 65 years of age. The total number of respiratory illness ED visits based on 3-day rolling averages are below January to April 2019 averages.

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*Discharge data from Kaiser San Rafael, MarinHealth and Novato Community Hospital show trends in ED visits due to respiratory illnesses and are updated as soon as data are available.

 

National and Statewide COVID-19 Activity

Visit the California Department of Public Health's COVID-19 website for updates on activity statewide and the Centers for Disease Control and Prevention's website for information on nationwide activity.

 

Definitions and Terminology

+Respiratory illnesses are identified using free-text chief complaint and structure primary impression fields in routinely collected Emergency Medical Services and Emergency Department data. Visits that mention at least one of the following (including common misspellings) were classified as those due to respiratory illnesses for the purposes of routine surveillance: influenza-like illness, influenza, fever, shortness of breath (only if with fever or cough in ED), difficulty breathing, respiratory distress, pneumonia, cough (only if with fever or shortness of breath in ED), sore throat, wheezing, bronchitis.