Measles Outbreak California: What’s Happening in 2025?

Yeah, I knowmeasles sounds like one of those diseases we left behind in old history books. The kind your grandma might talk about like it was just a bad rash and a few fevers.

But here's the thing: it's not.

And no, you're not imagining it. Measles is backagainand yes, it's showing up right here in California.

As of July 2025, there have been 18 confirmed measles cases across 13 counties. That's more than all of 2024. Nationally, we're looking at over 1,300 casesthe worst numbers since the early 90s. And get this: nearly every single one of those cases? Unvaccinated.

I'll be honestthis scares me a little. Not because I'm unprepared, but because I know how fast this virus moves. It's not just a fever and a rash. Measles can hospitalize. It can lead to pneumonia. In rare cases, it can cause brain swellingor worse.

But here's the good news: we already have the answer. It's not some experimental treatment or a future medical breakthrough.

It's the MMR vaccine. It's safe. It's been around for decades. And it worksreally, really well.

This isn't about fear-mongering. It's about honesty. It's about making sure you and your loved ones don't get caught off guard by something that's entirely preventable.

What Now?

As of mid-2025, California isn't in full outbreak modethankfully. But we are seeing a steady rise. And with major international airports in LAX, SFO, and San Diego, California is especially vulnerable to imported cases.

These 18 cases span cities and rural areas alike: Fresno, LA, Orange County, Sacramento, Long Beach, Tulareyou name it. Two young kids in Tulare County, neither vaccinated, caught it after potential exposure during travel. That's not unusual. Most cases in 2025 started overseasplaces where measles is still circulating.

Just to put that in perspective: we had only 4 cases in 2023, 15 in 2024. Now we're already past that count in under eight months. That's an uptick worth paying attention to.

Dr. Peter Chin-Hong at UCSF put it best when he called this a "canary in the coal mine." It's not yet widespread, but the warning signs are flashing.

Month	Cases
January	0
February	3
March	6
April	2
May	1
June	0
July (partial)	6+

(Data via CDPH)

Why Now?

You might be wondering: Why is this happening now? We eliminated measles in 2000. So how are we back here?

It's not just about travelthough that plays a big role. It's also about trust. About gaps. About misinformation that's spread faster than the virus itself.

Yes, most cases start with someone bringing it back from another country. But then it spreadsquietly, quicklyto pockets of unvaccinated people. And measles is incredibly contagious. One person with measles can infect 12 to 18 others. That's not a typo. It's more contagious than COVID ever was.

And with vaccination rates dippingeven slightlyin some communities, we're playing with fire.

Pretty much every public health expert will tell you: you need about 95% vaccination coverage to maintain herd immunity. California's kindergarten MMR rate is at 96.2% overallgreat, right? But drill down, and you'll find counties like Sutter hovering at just 75.8%. That's a recipe for an outbreak.

Dr. Chin-Hong said it perfectly: "We're like a dry forest. One spark, and it goes."

Nationally, it's even worse. Texas has seen 762 cases. New Mexico: 96. We're not thereyetbut we're close enough that it should make us pause.

The CDC now warns that the U.S. could lose its measles elimination status by the end of 2025. That's a big deal. It means we've gone from controlling the virus to potentially having it circulate on its own, year after year.

Know the Signs

Measles doesn't roll in quietly. But it doesn't announce itself clearly at first, either.

The early symptoms? They look a lot like the flu. Think:

• High feversometimes over 104F
• Dry, hacking cough
• Runny nose
• Red, watery eyes (doctors call it conjunctivitis)

This lasts a few days. Then, usually 24 days in, you might see tiny white spots inside the mouthcalled Koplik spots. They're not common in other illnesses, so if you spot them, get in touch with a doctor.

Next comes the rash. It starts on the face and moves downneck, chest, arms, legs. Red, blotchy, and it doesn't fade when you press it. That rash usually means the worst of the fever is coming.

And here's the scary part: people are contagious four days before the rash even shows up. That's why it spreads so fastsomeone could be walking through the mall, coughing, feeling a little "off," and not even know they have measles.

Day	Symptoms
13	Fever, cough, runny nose, red eyes
45	Koplik spots in mouth
57	Rash spreads from head to toes
8+	Fever may spike; cough persists
Contagious	4 days before rash 4 days after

Who's at Risk?

Let's be clear: measles doesn't play favorites. But some people are far more vulnerable than others.

Unvaccinated children under 5 are at the highest risk for serious complications. In fact, one in four will end up in the hospital if they get infected. Older adults, pregnant women, and people with weakened immune systemslike those undergoing cancer treatmentare also at serious risk.

And here's one group that often gets missed: people born between 1957 and 1968. Why? Because the early measles vaccines used back then weren't always effective. If you're in that range and unsure, don't assume you're immune.

Now, what about those who are vaccinated?

The truth is, the MMR vaccine is one of the most effective tools we've ever had. Two doses give you about 97% protection. One dose? Closer to 93%which sounds good, but in an outbreak, it's not enough.

And while no vaccine is 100%, breakthrough cases are rareonly about 4% of cases in recent years have been in fully vaccinated people. And when they do happen, symptoms are usually much milder.

Stay Protected

Here's the thing: we already know how to stop this.

The MMR vaccine has been used globally for over 50 years. Hundreds of millions of doses. No credible scientific study has ever linked it to autism. That myth has been debunked, re-debunked, and buried in research journalsyet it still lingers in corners of the internet.

So yes, it's safe. And yes, it works.

For kids, the schedule is simple:

• First dose at 1215 months
• Second dose at 46 years

If you're traveling internationally with a baby between 6 and 11 months? They can get an early first dose. It doesn't count toward the regular two-dose series, but it gives them temporary protection when they need it most.

And if you're an adult and can't remember if you were vaccinated?

Don't panic. You've got options.

You can check your California Digital Vaccine Record online. It's fast, secure, and free. Or, your doctor can order a measles titer testa simple blood draw that checks if you're immune.

And if you're still not sure? Get vaccinated. It's safe to receive another doseeven if you already had one or two. Your body won't hold a grudge.

Group	Recommendation
Children 1215 months	1st MMR dose
Children 46 years	2nd MMR dose
Teens/Adults (no record)	1 or 2 doses
International travelers	2 doses or proof of immunity
Pregnant women	Not during pregnancyvaccinate before or after
Immunocompromised	Consult doctormay need alternative protection

History Matters

This isn't the first time California's faced this.

Remember the 20142015 Disneyland outbreak? One unvaccinated visitor, possibly exposed in the Philippines, set off a chain reaction. Eventually, 131 people in California got sick. It spread to six other states, Canada, and Mexico.

That outbreak changed everything. It led to SB277, the law that removed personal belief exemptions for school vaccines. And yes, it was controversialbut it also helped push vaccination rates back up.

Then in 2019, we had 73 cases across six outbreaks. Again, tied to travel. One even hit a healthcare setting, infecting 21 peopleincluding staff.

The point? We've been here before. We know what works. And we know what happens when we let our guard down.

What You Can Do

You don't need to be a doctor or a scientist to make a difference.

Right now, the most powerful thing you can do is simple: check your family's vaccine status.

Go online. Pull up your California Digital Vaccine Record. See if you're up to date. If not, book a shot through MyTurn.ca.gov. Most pharmacies and clinics are ready to help.

And if you've been exposed or think you might have symptoms?

Pleasedon't walk into an ER or clinic. Call your doctor first. They'll help you come in safely, without risking others. Measles spreads through the air. One cough in a waiting room, and dozens could be exposed.

And if you're traveling?

Check the CDC's destination alerts. Some countries are seeing major measles outbreaks. If you're going to one, make sure you've had both dosesor get tested to confirm immunity.

For babies 611 months, that early MMR shot can be a lifesaver. And keep your records handy. You never know when you'll need them at a border or airport.

Final Thoughts

I get it. Talking about disease can feel heavy. It can feel overwhelming. And sometimes it's easier to just hope it doesn't happen to you.

But hope isn't a plan.

Measles is real. It's spreading. And 18 cases in California is not "just a few." It's a warning.

The good news? We're not helpless. We've got the tools. We've got the science. We've even got the laws and systems in place to protect communities.

But it only works if we use them.

So check your records. Talk to your doctor. Make sure your kids are protectednot just for their sake, but for the baby down the street who's too young to be vaccinated yet.

We're in this together. And the best outbreak? The one that never happens.

Take care of yourself. Take care of each other. And pleasedon't wait until it's too late.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.