It was the call Ray Dlugolecki had been dreading. And one he and other public health officials have been expecting.

The assistant director at Jackson County Public Health learned on Sunday afternoon about a confirmed case of measles, not just in his agency’s jurisdiction, but in one of its own buildings.

The previous week, an infected resident of eastern Jackson County had been inside the health department’s Lee’s Summit facility at 3651 N.E. Ralph Powell Road on two separate occasions.  

Dlugolecki understood that the highly contagious virus, which has been spreading with increasing success in communities around the country, had finally reached his doorstep. 

The welcome mat — a countywide vaccination rate too low for herd immunity — seemed to have made the scenario almost inevitable. 

County officials said the person likely contracted the virus on an Amtrak train traveling from Sedalia to Chicago on Aug. 27.

And now, that single case has exposed more than 250 people in Jackson County to measles, a dangerous virus that had been all but eliminated in the United States only a few years ago. That number doesn’t include anyone across the state line in Johnson County who could have also been exposed.  

“If we have pockets of individuals who are unvaccinated or can’t receive vaccines,” Dlugolecki said, “it gives the virus the opportunity to enter those communities and spread like wildfire.”

A link to another case

Immediately after learning about the Lee’s Summit exposure, a team of six Jackson County Public Health employees came into the office to begin trying to trace the infected person’s movements and figure out where they could have been infected. 

They worked into the night tracking down and notifying anyone who was in the room when the infected person was there or during a window after the person left. The measles virus can linger in the air as long as two hours.

So far, the health department has identified 251 people who had been exposed in Jackson County by this one case, including at least 10 who now have to quarantine for 21 days because they were not vaccinated or did not know their vaccination status. 

And area health officials expect the number of people exposed to grow.

The team also traced the infected individual’s movements to public spaces in Overland Park, where the Johnson County Department of Health and Environment also opened an investigation. 

Johnson County Health Director Charlie Hunt said no new cases had been identified by Sept. 16, but that could change, as symptoms can take seven to 14 days to show up.

Jackson County Public Health investigators said the local case is directly connected to another recent measles case of a Missouri resident who boarded Amtrak train 318, the Missouri River Runner, in Sedalia on Aug. 27 and rode to Chicago. Dlugolecki said evidence, including the timing of travel, symptom onset and epidemiologic information available, means the cases are likely linked.

According to state officials, two other measles cases have also stemmed from that person on the train — one in another person on board, and one in someone who lived in the same household — bringing the total cases related to the Amtrak exposure to four.

A recipe for an outbreak 

To achieve herd immunity for measles, at least 95% of people must be vaccinated. But across the country growing distrust in public health and misinformation about vaccines has caused that number to fall below that threshold. 

According to most recent data, in 2025 only 89.5% of Missouri kindergartners and 90.26% of Kansas kindergartners received the MMR vaccine, which protects against measles, mumps and rubella.

Recent data show a sharp rise in the number of parents seeking exemptions so their children can attend school without getting required shots. Missouri’s exemption rate jumped to 6.3% in the 2025-26 school year from 5.2% a year earlier, while Kansas’ jumped to 4.5% from 3.6%.

Growing fear stoked by misinformation about the safety of vaccines — including some coming from the White House — is likely partially to blame. And, since the COVID pandemic, public health guidance of almost any kind has been greeted with more skepticism overall. 

But whatever the cause of declining vaccine coverage, the result is a population potentially ripe for an outbreak, KC-area public health officials said. 

One infected person walking into a room with unvaccinated people could quickly spiral into a dangerous situation. In fact it is almost certain nine out of 10 unvaccinated people who are exposed will get sick. 

“People have to realize there are constant sparks getting thrown,” said Nathan Koffarnus, an epidemiologist with the Missouri Department of Health and Senior Services. “It’s just where they land, that’s the luck of the draw. … Now that there are more people walking around unprotected or underprotected, it’s a larger issue again.”

How measles spreads

The measles virus spreads through the air when someone who is infected coughs, sneezes or talks. It can also be picked up from a contaminated surface like a countertop or table.

Two shots of the MMR vaccine, the recommended dose, are 97% effective, meaning if 100 vaccinated people are exposed, only three might develop the virus. That makes the MMR vaccine one of the most effective out there. For comparison, the influenza vaccine is typically only 30% to 50% effective, in large part because influenza, like the virus that causes COVID, mutates, creating a changing target that is more difficult for a vaccine to hit. 

So far this year, of the 3,294 people known to have contracted measles in the United States, 95% were not vaccinated. 

But rarely, people who get an MMR vaccine still get sick. 

That was what happened in the recent Lee’s Summit measles case. Dlugolecki said the person at the center of the case had been vaccinated.

Catherine Satterwhite, executive director of the Center for Population Health and Equity at Kansas City University, said breakthrough cases happen with all vaccines. But in the case of measles, they are exceedingly rare. 

“For somebody to have a breakthrough case, a lot of things have to happen,” she said.

Rarely, a person’s immune system doesn’t respond as expected to the vaccine, leading them to have less protection. It is also possible a vaccine could be somehow corrupted, possibly because it wasn’t stored at the proper temperature, causing it to provide less protection. 

But even people who experience one of those extremely rare problems and get a breakthrough case of measles will still benefit from having been vaccinated, Satterwhite said. A breakthrough infection is usually less severe, comes with fewer serious side effects and is less easily passed on to others.

Satterwhite also said the Lee’s Summit breakthrough case provides a perfect illustration of why widespread vaccination is so important.

“We recommend vaccines on the population level to protect the people who either aren’t getting the (immune) response that we expect,” she said, “or who can’t get vaccinated.”

The few exceptions include infants. The first MMR dose isn’t recommended until a child turns 1, and the second is given around 5 years old. Some immunocompromised people also can’t receive the vaccine.

The cost to health and taxpayers

Health officials hope that incidents like the recent exposure in Missouri cause more people to understand the risks of not getting the shots.

Just being exposed, even without symptoms, will require someone who is not vaccinated to quarantine for 21 days. And developing measles can cause serious illness, including pneumonia, encephalitis and, in rare cases, death. An ongoing outbreak in Pennsylvania is linked to four deaths so far.

The virus, which was responsible for 500 deaths every year before vaccines became available, was declared eliminated in the United States in 2000. But that status, achieved when there was no continuous spread for more than 12 months, is at risk.

Beyond the health costs of a measles outbreak, responding to infections costs tax money. The Washington Post reported that investigating a Colorado outbreak involving nine children and one adult earlier this year cost taxpayers half a million dollars.

Jackson County Public Health could not yet offer an exact price tag for their recent case, but  Dlugolecki said the agency has already dedicated more than 150 staff hours to the response. That includes epidemiology and communicable disease investigators, leadership, communications, nursing and staff temporarily reassigned from other areas of the health department to help identify and contact exposed individuals, verify immunity, provide quarantine guidance and coordinate follow-up, he said. 

“That redistribution of staff also means other important public health work has had to pause or slow while the response is underway,” Dlugolecki said

Each exposed person may require multiple calls, vaccination record review, coordination with healthcare providers or employers, symptom monitoring and follow-up over the 21-day monitoring period. 

“The larger point is that a measles response can become very resource-intensive very quickly, even when it starts with a single case,” Dlugolecki said. “Much of that burden comes from the number of people who may have been exposed and the amount of work required to make sure they are identified, informed and appropriately managed.”

The vaccine worked too well?

Declining vaccination rates are the biggest reason the country is seeing more measles cases this year — the most in three decades. In some ways, said Koffarnus of the Missouri Department of Health and Senior Services, the vaccine may have been too effective.

“Cases have gone down so much over the past few decades that most people can’t remember ever knowing anyone that had it,” he said. “When you don’t see it and you don’t hear about it you think, ‘Well, that’s not something we have here in the United States.’ It’s tough for people to take that seriously and think, ‘Well, yeah, I probably should get the shot.’”

A popular meme often circulated among people who oppose the MMR vaccine involves “The Brady Bunch,” a 1960s sitcom. In a 1969 episode, the TV family happily navigates a measles outbreak, gleeful about time off school, appearing to experience very little distress. 

People cite the show as an example of why measles isn’t much to worry about, an inaccurate view, health officials said. 

But the truth is, the virus wasn’t much to worry about in recent years when vaccination rates reached 95% or higher. That wasn’t because the virus was no big deal — health experts are quick to point out —  but because the virus wasn’t spreading.

Clearly, that reality has changed, said Dlugolecki, something he didn’t expect when he began his public health career 13 years ago. He didn’t think waiting for the next report of a measles exposure would be part of his regular workload. 

“I was shocked to see it come back as it has over the last couple of years,” he said. “I didn’t expect to see massive outbreaks in dozens of states with deaths being reported.”