There’s a word most of us filed away in the same drawer as polio and rotary phones. Measles. Something your grandma had. Something we beat.

Then look at the board. The CDC counted 3,659 confirmed cases in 2026 as of September 24, past the 2,289 the country saw in all of 2025, which was itself the worst year in three decades. Cases have hit 45 states, and about 95 percent involve people who were unvaccinated or whose status is unknown. If sustained transmission is confirmed at a November review, the U.S. loses the measles elimination status it’s held since 2000.

Dr. Paula Marsland, a pediatrician with Monument Health in Spearfish, brings it up at every visit now.

“Doesn’t matter what you came in for,” she said on Monument Health’s Doc Talk podcast. “I want to make sure families are informed.”

Why it came back

Measles only lives in people. No animal reservoir, no soil. For years the pattern held: someone traveled internationally, came home carrying it, a case or two fizzled out.

What changed is the math underneath. Because measles spreads so easily, a community needs roughly a 95 percent vaccination rate to keep it from taking root. National estimates now sit around 91 to 93 percent, and in some counties it’s far lower. That’s where these outbreaks caught fire.

Marsland explains it like this: Picture an elevator. Someone with measles rides it, gets off, goes on with their day. Over the next two hours, ten unprotected people step into that elevator. Nine or ten of them get measles.

The droplets hang in the air after the person is gone, and a tiny amount does it. She says it’s three times more contagious than flu or COVID.

What it does

It starts with fever, often 103 to 105 degrees. Runny nose, cough, eyes gone bright red without the discharge you’d expect from pink eye. Two to four days later the rash arrives at the scalp and face and works down.

“It’s almost like somebody dumped a bucket of measles on you and started at the head,” Marsland said.

Then the complications. Pneumonia, ear infections, croup, dehydration. About one in a thousand children develop swelling of the brain. Some children die, and roughly 63 percent of this year’s cases are kids and teens.

There’s also a rare condition called SSPE that shows up an average of ten years after the infection, attacking the brain and nervous system. Not every child who gets measles develops it.

“Of those that do, it’s deadly,” she said. “It is almost universally fatal.”

And there’s immune amnesia. Your body makes memory cells after an infection or a vaccine. Marsland, a West Point graduate and Army veteran, calls them special forces cells. Measles infects them, so clearing the virus can cost a kid immunity to things they’d already beaten.

“I heard one infectious disease doctor describe it like starting daycare all over again,” she said.

What she hears from parents

“I do not blame parents for having questions, for being worried, because at the end of the day, we all have the same goal,” she said. “We want to keep kids safe.”

Has the vaccine changed? No. The MMR in use today started in 1971. One dose is about 93 percent effective, two doses gets you to 97. Is it given too young? A toddler’s immune system handles enormous exposure daily. “Licks the bus seat and you’re like, oh, no.” The autism study? Falsified. At least eighteen studies since found no link, and the doctor behind it lost his license.

Where she puts the responsibility might surprise you. “We as a medical community have let down the families and the worried parents, because we’ve done a poor job of listening.”

Who needs a shot

Born before 1957, you’re considered immune. Vaccinated between 1963 and 1967, get another dose, because a weaker vaccine was in use then. Vaccinated 1968 or later with two doses, you’re covered, no booster to chase.

Kids get one dose at 12 to 15 months and a second at 4 to 6 years. That second one can come early if you’re traveling.

If you think you’ve been exposed, call your clinic, even with no symptoms. Fever with cough, runny nose and red eyes, call. Then mask up and phone from the parking lot.

An exposure can mean quarantine for up to 21 days. Three weeks, everybody home.

“If you’re worried your kid might have been exposed, I really want to know,” Marsland said. “I want to take care of them right now.”