Public health leaders urge vaccination in Oregon’s largest measles outbreak in decades

Measles was declared eradicated in the U.S. in 2000, but as vaccination rates have fallen, the disease has popped back up. Oregon is experiencing the worst outbreak in the state since the early 1990s. With kids returning to school and measles being one of the most infectious of diseases, public health concerns are running high. Joining us to talk about all of this and update us on the latest COVID-19 news, is Paul Cieslak, medical director for the Acute and Communicable Disease Prevention Section and the Oregon Immunization Program at the Oregon Health Authority.

Note: The following transcript was created by a computer and edited by a volunteer.

Jenn Chávez: From the Gert Boyle Studio at OPB, this is Think Out Loud. I’m Jenn Chávez. Measles was declared eliminated in the United States in 2000. Twenty-four years later, as vaccination rates have decreased, it’s back. Oregon is experiencing its worst measles outbreak right now since the early nineties. And especially with kids returning to school, public health officials are urging children and adults to get vaccinated against the disease.

Here with me to fill us in is Dr. Paul Cieslak. He’s the medical director for Communicable Disease Prevention at the Oregon Health Authority. Dr. Cieslak, thank you very much for being with us.

Paul Cieslak: My pleasure.

Chávez: So several Oregon counties are in the midst of a measles outbreak right now, its worst in the state in more than 30 years. What can you tell us about the new cases we’ve been seeing this year in Oregon?

Cieslak: Most of them have been children and adolescents. And the county hardest hit has been Marion County, with 20 of our 30 cases. The next highest is Clackamas County, with nine of the 30. So most of the cases have been clustered around a region of northern Marion County and southern Clackamas County. All 30 of the cases that we have to date are in unvaccinated people.

Most Oregonians are vaccinated and have very little to worry about for measles. But this disease is spreading among unvaccinated people. And our recommendation is for people to get vaccinated. I suspect that some people may think “well, measles isn’t around.” As you noted, it was eliminated from the United States in the year 2000, which means we only see cases if they’re imported. And we’ve had many importations over the past 30 years, but they tend to run into a wall of immunized people and the disease can’t spread very far. But we’ve had sustained transmission now in this area for the past couple of months. And I’m concerned that the cat may have gotten out of the bag.

Chávez: And measles is extremely, extremely contagious when we’re talking about unvaccinated populations. How easily does this disease spread?

Cieslak: It’s probably the most contagious disease that we know of, although I think COVID with all of its mutations has perhaps gotten to the level where it approaches the contagiousness of measles. But it’s very contagious. It’s spread by the airborne route, which means that if somebody with measles coughs into a room, walks out of the room and you walk into it an hour later, if the room hasn’t been ventilated properly, you breathe the air which will contain the virus, and you could get measles if you’re not immune to it. So it’s highly contagious.

When it lands in a family with a lot of unvaccinated people, virtually all of them will contract the disease. That’s not true of most of the other diseases that we deal with. So somebody who’s contagious with measles and is out in the public, goes shopping, walks into a doctor’s office, anybody who is susceptible to the disease has a very high likelihood of contracting it.

Chávez: Wow. And because of how contagious it is, what are you or counties communicating to the public about possible exposure? You mentioned someone with measles maybe going to a grocery store or somewhere in public. How are you responding in that sense?

Cieslak: Well, whenever we get information about a public exposure, we do want to let the public know. To be honest with you though, we haven’t heard a lot of information about such exposures. Most of the people that we’ve interviewed tell us that the cases – and again these are mostly children and adolescents – haven’t been in public venues. It’s possible that it’s spreading from family to family rather than in large public settings. But we would notify people if there were exposures there.

And again, most people in those settings have very little to worry about. But if you’re not vaccinated, you have a significant chance of contracting the disease. And unfortunately, some people cannot get the vaccine. Children less than one year of age are not recommended to get it. It is a live virus vaccine, so we don’t give it to pregnant women, we don’t give it to severely immunocompromised people. And those folks are really dependent on the wall of immunity that the rest of us can establish if we get ourselves immune.

Chávez: And with the school year now underway for many students, what is top of mind for you in terms of mitigating this measles outbreak further?

Cieslak: Many schools in Oregon have very high vaccination rates. I think overall something like 86% of Oregon children have had all the required vaccines anyway. And a little over 90% have had two doses of measles-containing vaccine. But we’ve seen the exemption rate, the percentage of parents who are choosing exemptions for their children, rise steadily since the year 2000.

Around 2000 and up until then, there was a very steady rate of about 1% of parents of kindergartners saying, “I don’t want my child to receive one or more of the recommended vaccines.” And since the year 2000, the rate has risen steadily, until this year it’s its highest ever. We measure this on exclusion from school day in February, where if you don’t have the required vaccine or you don’t have an exemption, your child will be excluded from school. But many people can get out of the requirement by choosing an exemption and going through the process. It was 8.8% this past February. So that’s the highest we’ve ever seen. And that’s probably enough for us to see sustained measles transmission. If that rate is seen everywhere, we will probably see it.

To really stop measles, when we had measles elimination, we probably had over 95% [to] 96% of people in the country immune. And that’s why we were able to stop transmission entirely. We had a period of about three weeks in the United States back in the year 2000 where there were zero cases of measles before another case got imported. But that’s what it takes because it’s such a contagious disease. In general, this virus will find the 10% of people, if there are that many, who aren’t immune.

Chávez: So your message is, for children and adults, get that MMR vaccine, right? Measles, mumps, and rubella?

Cieslak: That’s correct. And I’m happy to say it’s one of our safest vaccines. There are a percentage of people who would get a rash after having the vaccine. But literally billions of doses have been given across the world. It’s used worldwide, it’s a very safe vaccine, and it’s very effective. A single dose is about 93% effective, and CDC tells us that two doses of vaccine bump up the protection to 97%. That’s the kind of rate you need in order to stem transmission of measles.

Chávez: And Dr. Cieslak, while you’re with us, I’d like to ask you briefly about another illness that’s been spreading in nearby Clark County, Washington: whooping cough. County health officials there are also concerned about the start of the school year. What is OHA watching for in terms of whooping cough in Oregon, and have there been cases here too?

Cieslak: Well, I’m sad to tell you that we have been dealing with an increase in the number of cases of whooping cough – the medical term is pertussis – for the past few months. We really had a reprieve from this disease during COVID. When people weren’t gathering in large numbers, a lot of the respiratory diseases really went to essentially zero or very close to it, and that was true of whooping cough. But we’ve seen a big resurgence of it over the past few months.

There has been a lot of the disease in the Portland tri-county area, and Lane County has been even harder hit around Eugene. Whooping cough is a bacterial disease, not a viral disease. And the bacteria makes some toxins that have you coughing. You can get some nasal congestion with it, but then you start coughing. And the coughing tends to come and fits. You’ll go for many minutes, maybe an hour or two without any coughing at all, and then you’ll start a coughing fit, and you won’t be able to stop.

And the other characteristic is that it lasts forever. Most of us when we get a cold, we’re coughing for a week or two or maybe three at the outside. But the cough of whooping cough can last months. Some have dubbed it the 100-day cough. It’s that nagging cough that doesn’t seem to go away like you expect that it would.

Most adults and adolescents will get over it fine. The real problem is when it hits infants, infants too young to be vaccinated, under six months of age in particular. They’re the ones who land in the hospital, and we have had occasional fatalities from pertussis. And because of that high risk in infants, about 10 years ago, maybe 12 years ago, the CDC started recommending that women get vaccinated during each pregnancy, because they will make antibody and transfer to baby across the placenta. And this will protect baby right from the moment of birth. We’ve done studies that show upwards of 75% protection of the baby if mom gets vaccinated during pregnancy.

Chávez: Thank you doctor. And we just have a couple moments left, but I do want to ask about COVID. Seems like a lot of people have had COVID lately around Oregon, and I know that there is a new vaccine on the way. Can you tell us when Oregonians will be able to get that updated vaccine?

Cieslak: Well, strictly speaking, I cannot, because I haven’t heard any firm dates from anybody. But my understanding is that it should be arriving in doctors offices and pharmacies as soon as this week. So I’m hoping that over Labor Day weekend, we’ll see an influx of vaccine. But I don’t actually have inside knowledge on this. I’m hoping to get my vaccine as well. I’m 64 years old, and I certainly intend to get the updated vaccine. It’s gonna be recommended for everybody six months of age and older.

Chávez: Well, Dr. Cieslak, thank you so much for joining us with all of this important information. We appreciate your time today.

Cieslak: Thanks for having me.

Chávez: Dr. Paul Cieslak is the medical director for communicable disease prevention at the Oregon Health Authority.

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