Your Local Epidemiologist in California
Welcome to the California edition of Your Local Epidemiologist (YLE). I bring public health science directly to your inbox once a week, making it understandable, relevant, and useful. It’s for Californians by a Californian.
Who am I?
I’m Matt Willis, Your Local Epidemiologist in California. After starting my career as a primary care doc I joined the CDC, doing outbreak investigations in the US and abroad. From 2013 to 2024 I served as the Public Health Officer for Marin County. Whether caring for individual patients or whole communities, I’ve learned the best way to support health is listening closely to those I’m serving, and translating science into actionable guidance. I live in the Bay Area, where I grew up, and where my wife and I raised our three kids and two dogs. When I’m not writing these reports, I’m engaged in research on the health impacts of climate change, or out exploring our beautiful state.
What you’ll find here
As the Public Health Officer in Marin County, I worked to bring calm and clarity to the twists and turns of the pandemic—from variants to vaccines and beyond — through regular communication including newsletters and videos. As a member of the YLE team, I’ll bring that same approach to the wide range of health topics facing us in California.
Some highlights:
Public health news you can use.
Updates on outbreaks within the state, and how to protect yourself and loved ones
Guidance for climate events, including heat waves, wildfires, and water and air quality concerns
The latest health rumors and what is (and is not) accurate about them.
Translating how federal and state policies can affect our health in California
Updates on emerging research, trends, and technology, including vaccines.
Plus, some good news to brighten your week!
Public health is everywhere—it touches every aspect of our lives. My goal is to help you see it, understand it, and use it.
How you can get involved
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You also get:
Practical resources: Subscriber-only content and events, including bi-monthly webinars, downloadable PDFs and bonus resources that help you take action.
Full access to the archive: We’ll always make sure that timely, critical information is available for all — but posts more than 90 days old are subscriber-only.
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Join Our Community!
Join the YLE Everywhere community and get bonus access to our flagship national newsletter.
Subscribe to this newsletter — and share what you learn with your community.
Donate to support our mission. Contributions are tax-deductible through our fiscal sponsor, Social Good Fund.
Not in the California area? Explore the mothership — Your Local Epidemiologist national version — with 379,000+ subscribers.
Thank you for being part of this journey to elevate evidence-based communication in public health. It’s needed now more than ever.
In health,
Matt Willis
