Health officials warn Oregon measles outbreak is growing

As of last week, Oregon had reported 20 measles cases since the start of 2026. Measles was declared eradicated in the U.S. in 2000, but falling vaccination rates have driven outbreaks in more than half of U.S. states so far this year. Health officials warn that community transmission in Oregon is beginning to grow and have asked for the public’s help in curbing the spread.

Dean Sidelinger is a health officer and state epidemiologist for the Oregon Health Authority. He joins us with more details about where the outbreak stands and how people can stay safe.

Note: The following transcript was transcribed digitally and validated for accuracy, readability and formatting by an OPB volunteer.

Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. Oregon has reported 20 measles cases since the start of this year. Health officials say this could become the worst year in the state since the highly contagious disease was eradicated in the U.S. more than 25 years ago. Dean Sidelinger is the state epidemiologist, he joins us now. It’s great to have you back on the show.

Dean Sidelinger: Thanks for having me.

Miller: I looked back at our calendar. We talked about measles outbreaks in June of 2025 and in August of 2024. What’s different about this current outbreak?

Sidelinger: Here we are just three-and-a-half months into the year and we’re reporting 20 cases. That’s in comparison to just over 30 cases that we reported in 2024, which was our biggest year in decades.

Miller: The year in total?

Sidelinger: In total.

Miller: And we’re only three-and-a-half months in, you’re saying?

Sidelinger: Right. And the cases we’re seeing now are, many of them, we don’t know where they came from. These aren’t returning travelers who came and were exposed in another state or another country. We’re able to make some connections between some cases and we reported some linked cases last week, but for some of them we don’t know where they’re coming from.

And also, we know that in testing measles in the wastewater, which is a tool we weren’t using a couple of years ago, we see counties that have measles detected in their wastewater where we don’t have a report of a case. So we know that those 20 cases represent the tip of the iceberg of what’s actually happening.

So that’s why we’re talking about measles a lot because we want people to know and know what the risk is.

Miller: I want to go back to the first part that you were leading with there, that you haven’t been able to trace the origin of a lot of these cases. Am I right that that’s, say, in contrast to a school-based outbreak, someplace where you can say that there were these X number of cases?

Sidelinger: Correct.

Miller: No one wants to see a huge outbreak in some place. But you’re saying that in some ways it’s even more worrisome that there are these 20 cases, that somehow somebody got measles, but you don’t even exactly know how. In its own way, it seems like that’s a bigger problem?

Sidelinger: Correct, it represents hidden spread. Measles, it’s one of the most contagious viruses we know. People can spread the virus before they get too sick. So it’s not like these are sick people who know they have measles who are out in our community, but people who maybe just started feeling sick and have some mild symptoms, and during that time they can expose others. It indicates that they’re not going to seek care when they have measles, which is good that they’re not sick enough to seek care, but it’s when they seek care that the provider reports it to us or a lab is obtained and it gets reported to us.

So I think it’s that kind of hidden spread that goes under the radar that we’re worried about, and why we think these cases are going to increase pretty substantially and be with us for a while.

Miller: How does Oregon compare to other states right now in terms of case numbers?

Sidelinger: Luckily, we’re much lower than states like Utah and South Carolina, which have experienced and are experiencing some very large outbreaks. But I think well over 30 states have reported measles cases already this year. And while 20 doesn’t seem like a lot, we know there are more, and that’s higher than many other states. So that’s why we’re talking to folks.

And overall, I want to reassure people, if you’re fully vaccinated against measles, your kids are fully vaccinated, you’re very well protected. So this year is not going to be much different to you than previous years. But if you are not vaccinated or have children who are not vaccinated, either because they’re under 1 [years old], or you’ve chosen not to start their vaccines when they turn 1 [years old], or you’re immunocompromised – like you’re getting cancer chemotherapy or taking medications that cause your immune system not to work – there is a chance you could be exposed to measles and get sick this year, which is not something we said last year because we didn’t see this spread.

Miller: Let’s talk about what can happen when you get sick. The first measles-related hospitalization in Oregon this year was reported just a few days ago. How serious can measles be?

Sidelinger: So I want to dispel the rumor that measles is just fever with a rash. Certainly, those are key characteristics. We start with some runny nose, congestion, watery red eyes and a fever. Shortly after the fever starts or about the same time, we develop a rash, typically on our face, that travels downward. And even that makes people miserable. Children with measles are miserable. They feel awful, adults feel awful. It’s not a great illness to have.

On top of that, it can infect the lungs and we can get pneumonia. It can cause swelling and inflammation in the brain. Those often require hospitalizations. So hospitalizations are not that rare with measles. They’re rare when measles is rare, but as the numbers go up, we expect to see more people hospitalized.

And we don’t have a treatment for measles. We have a great vaccine that works to prevent measles, but there’s no treatment. So we can treat the symptoms of the pneumonia, we can try and treat the inflammation in the brain, but we can’t treat the virus itself. And that’s why, before we eliminated this disease with the measles, mumps and rubella shot, 1 in 1,000 people died from this. And that’s also a possibility. Last year in this country, we had three people die from measles. That’s tragic because, in my mind, those deaths were preventable.

Miller: When you say – and I said it in my intro, this is language that has been pretty common for two-and-a-half decades – that measles was eradicated in the U.S., what does that mean?

Sidelinger: So people hear that and they’re like, “but I hear about measles every now and again.” What it means is that measles isn’t regularly transmitting in this country. The cases we saw were sporadic, typically traced to someone returning from another country who had measles. They may have exposed people in their household or people in a health care setting or another setting where they were. We can usually get a handle on that, hear who they’re around, know those cases, have those people stay home who were exposed and not immune, and prevent the spread or limit the spread. That’s what measles elimination means. And since the early 2000s, the United States has been in that situation, where those measles outbreaks happened occasionally. Some were a little larger than the others, but we could get control of them.

We’ve seen measles spreading since early 2025, initially large outbreaks in Texas, many other states with outbreaks. And that spread has continued now for about a year-and-a-half in this country. That’s why we’ll likely lose our measles elimination status this year. I would say if you just look at the spread and look at the cases and how they’re reported each week, I think we’re there. But we have to analyze all the data and the WHO will make that decision in the fall.

Miller: It does seem like that’s what you were saying earlier in terms of the spread already in Oregon this year. If it’s not tied to obvious outbreaks, it seems almost by definition that it’s endemic or at least common enough, even today in Oregon without a huge number of cases, that it’s not eliminated in Oregon. And we’re not the worst state.

Sidelinger: Right. And I would feel comfortable saying that in Oregon, what we’re seeing is that the disease is likely endemic for now and that it’s not eliminated. Again, the official word on the country losing elimination status and measles being endemic again comes from us sharing the data with the WHO, them examining all the data and making a decision. Like I said, we expect those meetings and those discussions to happen in the fall, and likely we’ll follow the same path Canada did last year when they lost their measles elimination status.

Miller: Speaking of the federal level, what is the messaging from the federal government right now about the MMR vaccine?

Sidelinger: We’ve been getting mixed messages, particularly from the political appointees in the federal government. It’s not a secret that Secretary Kennedy, for many years, headed a not-for-profit that expressed a lot of skepticism about vaccines and was responsible for a lot of the misinformation that we saw online. That was when he was in the private sector, but that kind of dialogue has continued. Recently, he has said he supports MMR vaccine in children. But I think those expressions of support are few and far between compared to the rhetoric we’ve heard throughout his career.

We have some dedicated public health professionals and partners at the CDC who continue to work and support states on our measles needs and answer our questions. But the workforce there is much smaller and has been really impacted by the cuts at the federal government. We know that the ACIP committee, which met last year, expressed a lot of skepticism about vaccines, including MMR and how we monitor safety. So that, I think, has spread out into the general public, where we’re seeing more distrust and questions about vaccines.

I will say, as a pediatrician, I’ve had so many conversations with parents. I support them, if they have concerns, if they have questions, get those answered, bring them up with their provider, because they’re making a decision for their child. But I can say unequivocally in looking at the data, we’ve used the MMR vaccine for decades. It’s been very well studied. It led to the elimination of measles in this country, which meant no one had to worry about getting measles, including parents of children under 1 [years old] who are not eligible to get vaccinated routinely. And now, we’ve lost that. That safety is gone.

Initially, there was concern … Dr. Wakefield, his study linking MMR to autism. Completely not a reputable study: forged data was retracted, he lost his license. But that started this skepticism, and time and time again, large studies have shown that that link isn’t there. But yet we still hear that from some of the members who were on the ACIP last year and from our secretary. It’s hard to combat that. And I know in public health, we got to rebuild that trust.

Miller: Maybe we’ll get the latest non-medical exemption data, but from May of 2025, the latest I’ve seen, close to 10% – a record – of Oregon parents opted their kids out of some number of required vaccines. What specific message do you have for parents?

Sidelinger: I have a couple of messages. I will say, the flip side of that number is 9 out of 10 parents have chosen to fully vaccinate their children with the safe and effective vaccines that we’ve used for decades. That provides their kids protection against these diseases, and as a byproduct, also provides protection to all of us in the community. It’s not a trade-off. So that’s great. Sometimes if you read things online or follow social media, you may think “well, no one’s vaccinating their kids anymore.” And I want to say that I thank and appreciate the 9 out of 10 people who’ve had those conversations with their providers and vaccinate their kids.

I also want to say, for a parent who’s concerned or has questions about vaccines, that’s normal. Talk to your child’s trusted health care provider. Look at the American Academy of Pediatrics website, look at the OHA website, and follow some trusted links that describe vaccines and the ongoing monitoring and safety that happens.

And also, for parents who maybe were still concerned and chose not to vaccinate their children, the situation in 2026 is very different than it was in 2025, or three years ago, or four years ago. Measles is going to become more common in Oregon, as it already has in other states. The decision you made five years ago for your child might be different this year because the risk of measles is so much higher, whereas the risk of measles wasn’t as high five years ago. A safe vaccine that provides lifelong protection is available and your decision might change based on the situation we’re facing right now.

Miller: Dean Sidelinger, thanks very much.

Sidelinger: Thank you.

Miller: Dean Sidelinger is a health officer and state epidemiologist for the Oregon Health Authority.

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