Measles 101: What It Is, Why It's Dangerous, and How to Stay Protected

Measles has returned to Illinois, and case counts across the United States have now exceeded 1,000. We’ve seen your questions and heard your concerns, and now we have answers.

In this episode of This Is Public Health, we cover all you need to know to keep yourself and your loved ones protected from measles. Dr. Jennifer Seo, Pediatric Medicine Medical Advisor at IDPH, discusses what measles is, addresses common misconceptions about measles treatments – and emphasizes why vaccination is the best, and only, protection against measles.

Jim Leach: Welcome to This Is Public Health, a podcast from the Illinois Department of Public Health. You've undoubtedly been hearing a lot lately about measles with some of the highest nationwide case totals in years. In recent weeks, we've seen cases returned to Illinois as well, so on this episode we'll go through everything you need to know about an illness that was once thought to have been virtually eradicated in the US. Our guest is Dr. Jennifer Seo. She's Pediatric Medicine Medical Advisor at IDPH. Dr. Seo, thanks so much for joining us.

Dr. Jennifer Seo: Thanks for having me.

Jim Leach: Well even though you are the Pediatric Medicine Medical Advisor, this is obviously an illness that has potential impacts not only for children but for adults as well. So, let's start with just an overview of what exactly measles is, what symptoms it produces, and why it can be potentially very serious for some people who get it.

Dr. Jennifer Seo: So, measles is a highly contagious infection caused by a virus, but it's a disease that's preventable through vaccination. In terms of the symptoms that measles causes, about 10 days after someone's infected, they can develop a high fever, so a fever even over 104 degrees Fahrenheit, cough, runny nose, red watery eyes, and then about 4 days after the start of those symptoms, they'll develop the rash that measles is known for. So, red spots and bumps that start at the hairline that will move down the face and then down to the rest of the body.

Dr. Jennifer Seo: So, these symptoms probably to many people sound familiar. They are symptoms that people will get with viruses. Children in particular can get all sorts of rashes, but what's important to remember is that measles isn't just another little rash. It can actually cause serious complications, and the risk of complications is higher in children under the age of 5 years, for adults over 20 years of age so that's a lot of people, pregnant people, people with weakened immune systems.

Dr. Jennifer Seo: And to give you an idea of what these complications look like, so one in 5 people with measles will need to be hospitalized for treatment. One in 20 children with measles will get pneumonia or an infection in their lungs, and that's the most common cause of death in young children.

Dr. Jennifer Seo: One in 1,000 children who have measles will get encephalitis, or an inflammation and swelling of the brain that can lead to seizures, deafness, long term intellectual disability, and there's also something called Subacute Sclerosing Panencephalitis. It's very rare, but it's fatal. So, it's a disease of the central nervous system in the brain that's caused by measles. What will happen is someone will recover from measles, go back to seeming like they're normal, and then about 7 to 10 years afterwards, they'll develop this disease. And again, it causes death, so very rare but fatal which is why we take measles seriously.

Dr. Jennifer Seo: And the other thing to keep in mind is that for every 1,000 people with measles, we see 1 to 3 deaths, and we've already seen that here in the United States this year. We've had over 1,000 cases, and we've seen 3 deaths, and 2 of those deaths were in school-aged children, so measles is a disease that we want everyone to be informed about because we have a tool to prevent it, and that's a vaccine.

Jim Leach: Truly not something that anyone should take lightly. Now you mentioned that this is a highly contagious illness, so exactly how is measles spread and if someone does have measles symptoms, what should they do?

Dr. Jennifer Seo: Measles is spread not only by direct contact with an infected person's nasal or throat secretions, it's actually also spread through the air – so when someone coughs, sneezes, even when someone who's infected with measles simply breathes or talks. And the thing with measles is it's really good at traveling through the air and staying in the air, so it can stay in the air up to 2 hours after an infected person has left a room or an area. So, someone could walk in after that person has already gone within those 2 hours and become infected with measles. So again, the reason why we take measles very seriously.

Dr. Jennifer Seo: If someone has symptoms of measles or they're worried they have measles, this is why we also want them to stay at home and away from others. Someone is considered contagious 4 days before the rash appears up until 4 days after the rash started. So, if you think you have symptoms of measles, you're worried, stay at home away from others, call your health care provider to get guidance, but also you should call your health care provider in advance so that they can prepare to not only treat you but also prepare to limit exposures to others who may be in their health care facility.

Dr. Jennifer Seo: And if you or your child have been exposed to someone with measles, and you know you aren’t immune, meaning you haven't been vaccinated or have other proof of immunity, or you're not sure if you're immune, you should also stay home, call your health care provider again, not only to just get guidance on what to do after that, but also because you could be eligible for what we call post-exposure prophylaxis to potentially protect against infection or lessen the severity of the illness if you have an infection, and this could be by getting a vaccine within 72 hours after being exposed, or there's also something called immune globulin that some individuals may be able to get within 6 days of being exposed.

Dr. Jennifer Seo: So, the important thing to keep in mind – measles spreads really easily in the air. If you have symptoms of measles or you have been exposed, stay at home away from others. Call your health care provider to get guidance.

Jim Leach: Well older members of our audience will recall a time when measles was very common. It seemed like almost everyone got it or had a family member who had it or something, but then over the years, it nearly went away completely. So, how did that happen, and why is it now making a comeback again?

Dr. Jennifer Seo: Right, so before the measles vaccine became available in 1963, nearly all children got measles by the time they were 15 years old, and it was estimated that every year in the United States, there were about 3 to 4 million infections, 48,000 hospitalizations, 1,000 people suffered from encephalitis – that swelling or inflammation of the brain – and there were about 400 to 500 people who would die every year from measles. But then the vaccine was introduced in 1963, and it drastically reduced the cases of measles, the hospitalizations, the deaths, the suffering from the measles infection.

Dr. Jennifer Seo: And in fact, in the year 2000, the United States achieved measles elimination status, meaning measles was no longer considered endemic in our country because there wasn't continuous spread of measles. But unfortunately, we've seen a return of cases of measles and a rise in the cases of measles, and that's because we've seen fewer people getting vaccinated. We've had declines in our vaccination rates against measles and other diseases, and so as I mentioned again, here in the United States as of May 15th of this year, we've had over 1,000 cases of measles already in 31 states including Illinois. We've unfortunately had 3 deaths. In fact, those were the first deaths in a decade that we had seen from measles. 2 of them again in school-aged children – the first pediatric deaths in over 2 decades. These were all in unvaccinated individuals, so something that again, we want people to be informed about and to get protected again through vaccination.

Jim Leach: We want to talk in more detail about immunization here as we're looking at measles on This Is Public Health with the Illinois Department of Public Health. Our guest Dr. Jennifer Seo, Pediatric Medicine Medical Advisor at IDPH. So, on this question of immunization, how effective is the current measles vaccine? Is it safe? Does it cause complications?

Dr. Jennifer Seo: First of all, the measles vaccine is one of the most effective vaccines that we have. One dose is 93% effective. 2 doses is 97% effective. And it is a safe vaccine. It's been around for over 50 years, that's over half a century.

Dr. Jennifer Seo: Now with any vaccine or medication, there may be some side effects, but first I'll mention it is extremely, extremely rare. So, there may be some people who are allergic to a component or ingredient of the measles vaccine. It's the Measles Mumps Rubella vaccine, MMR vaccine, and so that's why when you get your first dose your health care provider will be monitoring and also giving you guidance in terms of symptoms to look for, but that's extremely rare.

Dr. Jennifer Seo: There are other side effects that are more common, again the side effects that many people will get after a vaccine. So, some people might experience a bit of a fever or some soreness in the arm. Some people actually from the MMR vaccine may develop a rash that might look like measles, but it's not measles disease. It's actually a sign that your immune system is responding to the vaccine and that measles component of the vaccine.

Dr. Jennifer Seo: Some other less common symptoms, some people may experience some joint pains and stiffness. This is more common in teenage and adult females. Some people rarely may get swelling of the glands around their cheeks and their neck. It's because that Measles Mumps Rubella vaccine protects against mumps, and again, this isn't mumps disease, but it's a sign that your immune system is doing its job.

Dr. Jennifer Seo: And very rarely some individuals may have a temporary decrease in their platelet counts that could affect how quickly the body can stop bleeding, but it usually goes away without any treatment. It's not life threatening. Again, it's temporary. And then there is a very small risk of febrile seizures or seizure that can be caused by fever that we see in infants and young children. Again, no long-term effects from this.

Dr. Jennifer Seo: And one thing to keep in mind is that this risk, again is a small risk, but it does go up as an infant gets older, so this is all the more reason to get your infant vaccinated as soon as they are eligible when they turn 12 months old.

Dr. Jennifer Seo: So, I think that the thing to keep in mind is all vaccines, all medications have side effects. For the measles vaccine, these are temporary and in exchange you get a lifetime of protection against measles. And it's important for people to be aware of when they should get vaccinated, so let me just cover that quickly.

Dr. Jennifer Seo: So, all children should get their first dose of the measles vaccine when they're 12 to 15 months of age. That second dose is when they're 4 to 6 years of age, but that second dose can be given as soon as 28 days after the first if it's needed or recommended. Children are required to be up to date on their measles vaccination to be in a daycare here in Illinois or a childcare facility, and also they need to be up to date for school. So, my advice to any parents or guardians out there is don't wait to get your children vaccinated when the school or the daycare is asking for paperwork. Go ahead and get them vaccinated now when they're 12 months old and then that second dose when they're 4 years old.

Dr. Jennifer Seo: And then for adults, you should all have at least one dose of the MMR vaccine unless you were born before 1957 because as I mentioned there was so much measles circulating you likely were infected and you're presumed to be immune. There are some higher risk adults because of their jobs or their setting where they may need 2 doses of the MMR, and those would be health care workers, people attending post-secondary educational institutions – in other words colleges or universities. It's also required for childcare facility workers here in Illinois for you to have 2 doses.

Dr. Jennifer Seo: And if anyone's traveling internationally, all individuals 12 months and older, you should have 2 doses of the MMR vaccine and again those doses should be given at least 28 days apart. If you have an infant who is 6 to 11 months old, again, if you're traveling internationally, your infant should actually get a dose of MMR. What's important to know is that if they get this early, they still need to get 2 doses of the MMR once they're 12 months old to complete their regular series.

Dr. Jennifer Seo: And then because we have a lot of measles cases here in the United States, if you are traveling to an area domestically with an outbreak and you are 12 months of age or older, make sure you have your 2 doses of MMR. If you have an infant who's 6 to 11 months old, talk to your health care provider about that situation because it depends on whether the vaccine is being recommended for babies 6 to 11 months old in that particular outbreak area. So, lots of reasons to get vaccinated. We hope everyone will get protected if they're not already.

Jim Leach: We will, by the way, give you some information on where you can find more details or go back to refresh your information on these details on our website. A lot to keep track of here, and it is important to know how and when you should be vaccinated and be up to date on that. But, we have actually seen some conflicting information about people, particularly in roughly my age group of people, who may have been vaccinated at some time in the 1960s and some questions about whether they are in fact fully immunized. So, what do people need to know about their immunization status, and will some people need a booster shot?

Dr. Jennifer Seo: Right, so again, if you were born before 1957, you're presumed immune, and so there isn't a dose of the MMR that's recommended for you. Although if you're not sure you're immune and you want to get vaccinated, you certainly can.

Dr. Jennifer Seo: If you got vaccinated between 1963 and 1967 when the measles vaccines first became available, there were actually 2 different vaccines that were out at that time. One of them was an inactivated or killed virus vaccine that was found to be less effective later on, and so if you know that you got that inactivated or killed virus version of the vaccine or you're not sure and you got vaccinated during that time 1963 to 1967, you should get at least another dose of MMR.

Dr. Jennifer Seo: If you are overall not sure whether you are vaccinated and you cannot find your measles vaccination records, it doesn't hurt to get vaccinated again, even if you may have gotten the vaccine before. And if for some reason you can't get vaccinated, you can actually talk to your health care provider about checking something called titers. It's a blood test that can show whether you're immune to measles or not.

Dr. Jennifer Seo: In terms of getting a booster, again, there are certain adults who should make sure you have 2 doses of the MMR because you're at higher risk of being exposed, but actually that second dose that we routinely give in childhood is not considered a booster. It's actually a dose to try to catch those individuals who might not have become fully immune after that first dose of MMR. So, as a reminder, one dose is 93% effective. 2 doses is 97% effective, so that second dose is to try to make sure that those who didn't fully respond to the first dose that they're immune as well.

Jim Leach: You're listening to This Is Public Health with the Illinois Department of Public Health. IDPH recently updated its school's measles vaccine coverage dashboard and also launched a measles outbreak simulator. So, talk if you would, Dr. Jen Seo, about these tools and how we're doing with measles vaccination rates in our state.

Dr. Jennifer Seo: So, we're really excited about both of these dashboards that we have recently launched. One of them is the school vaccination coverage dashboard. It was actually first released last year as a tool for school communities, the public to be aware of what the school vaccination rates were, and this is based on data that the Illinois State Board of Education collects every year from schools. So, for parents and guardians, those vaccination records that you give to your schools, it's helpful information for us to keep track of how well we're doing as the state in terms of vaccination. This dashboard shows vaccination rates for not just the measles vaccine, but for all of the required vaccinations for school, and it's the most comprehensive data that we have on vaccination rates since it is required of all children.

Dr. Jennifer Seo: The second dashboard tool that we have released is a school measles outbreak simulator. So, this actually takes the data that we have on our school vaccination coverage dashboard for this current school year – 2024 to 2025 – and what it does is it estimates the likelihood and the potential size of the measles outbreak should someone with measles come into a school. So, you can actually find your school and see, “Okay, what is the likelihood that there might be a big outbreak in my school? How long and how big might that outbreak be?” And we're hoping that school officials, local public health officials, and the public as well, that they'll use this tool to see what an individual school's risk of an outbreak is so that they can take some action to prevent it. So, that includes ensuring vaccination of all the students and the broader school community.

Dr. Jennifer Seo: In terms of how we're doing overall with our school vaccination rates for measles, our rate this school year stayed about the same as where it was last year. So, this year we're at 95.8%. Our goal is to get to 96% or higher overall as a state but also within individual counties and individual schools themselves. So, about the same as last year. We're not where we were 10 years ago when we were at 97.8%, and over the years across the country too, we've seen a decline in vaccination rates. Something that we're trying to bring back up, so some work to be done.

Dr. Jennifer Seo: I think the other thing to keep in mind is our state as a whole, we're doing okay. Again, we want to be higher than 95.8%, but if you look at individual counties or even individual schools, you will see that there are several counties and schools that are below 96%. Some below 91% coverage. And what’s concerning is that we've seen a steady decline in the percentage of schools who are at that goal of 96% or higher. So, what we're hoping will come of these dashboards is, again, that school officials, school communities will be informed, but that also communities will start talking about it, start talking about measles vaccination, talk to your neighbor. Make sure everyone is vaccinated because again we have a tool to prevent this disease.

Jim Leach: Really important to have information but also important to guard against misinformation, and as we've seen more attention being given to measles, we're also seeing reports about supposed alternative treatments, things along those lines. So, how is measles treated? And do these alternatives work, or do they potentially cause more problems than they solve?

Dr. Jennifer Seo: So, the thing to keep in mind is there is no specific treatment for measles. The care that we give for measles is called supportive care, so it's care that we do to relieve symptoms of measles like trying to relieve fevers. So, no specific treatment for measles.

Dr. Jennifer Seo: Some folks may have heard about Vitamin A. Vitamin A does not prevent or treat measles. What it can do is it can reduce complications of measles in malnourished children, and it might do the same in other children because what the measles infection does is it depletes your body of Vitamin A. But again, it's not a cure for measles, and too much Vitamin A can actually be dangerous. It can cause damage to your liver, to your bones, your central nervous system and brain, your skin, so this isn't something that individuals should be taking out there. Again, it doesn't prevent measles. You should get vaccinated if you want to prevent measles. And it doesn't treat measles, so something to be aware of.

Dr. Jennifer Seo: Some people may have also heard about budesonide or an inhaled corticosteroid. This is a medication we use to help with inflammation in the lung airways that might be caused by asthma or wheezing that's triggered by measles. But again, it's not a cure for measles. It’s treating and relieving a symptom that could be caused by measles.

Dr. Jennifer Seo: We've also heard of individuals talking about clarithromycin or other antibiotics for measles. Again, not a treatment for measles because antibiotics only treat bacterial infections, and measles is a viral infection.

Dr. Jennifer Seo: So, no specific treatment for measles. There are things that we can do to support individuals who have measles and the symptoms that they have, but again, the important thing and what people should be focusing on is preventing measles by getting vaccinated.

Jim Leach: We have thrown a lot of information at people today, and it's a lot to keep track of, but fortunately IDPH has recently updated its measles page on its website and added some tools to help people keep tabs on the illness. So, tell me what more people can do to stay informed.

Dr. Jennifer Seo: Right, so we have been constantly updating our measles website here at the Illinois Department of Public Health, so dph.illinois.gov/measles. A lot of what we've talked about today is actually on that website, so if you need a refresher on all the information you've received, you can go there.

Dr. Jennifer Seo: We are also updating our case counts in terms of our measles cases here in Illinois. We are also updating information on public exposure sites, so health care providers or members of the public can go to our website, see where someone with measles may have been to check and make sure you haven't been exposed. We also have resources for health care providers and schools, so different tools and guidance that you can use to protect your particular communities in your areas. So, lots of information.

Dr. Jennifer Seo: We hope that everyone will continue to stay informed because we are continuing to see measles cases, and we want to make sure everyone's staying abreast of what's going on, not only with measles but in public health in general.

Jim Leach: Again, you'll find much more at dph.illinois.gov. There is a measles link on the home page. I want to again thank our guest Dr. Jennifer Seo, Pediatric Medicine Medical Advisor at the Illinois Department of Public Health, and thanks to everyone for joining us here. Join us next time for another edition of This Is Public Health with the Illinois Department of Public Health.