In late March, a four-year-old in Erie County was diagnosed with measles, a highly contagious and incurable disease that, in rare cases, can cause brain damage and death.
The child, who the county did not identify to the Capital-Star, had attended day care at Creative Learning Childcare in Erie, where 160 kids were enrolled, while likely infected. According to County Executive Brenton Davis, some children under 1-years-old, the age when children typically receive their measles vaccination, may have been exposed.
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It was the third diagnosed case in Erie County this year, which had not had a single, documented one since 1991. And it was the sixth case in Pennsylvania. There has been one confirmed case each in Bucks, Montgomery and Philadelphia counties as well.
Currently, the U.S. is experiencing one of its largest measles outbreaks in decades, largely due to a cluster of cases among a Texas Mennonite community. There have been more than 600 cases across the country in 2025 alone, the most cases on record since 2019 — and it's only April. Three people have died, two of them children.
The resurgence of the disease, which the World Health Organization declared eliminated in the U.S. in 2000, is largely due to declining vaccination rates. Because it is so contagious, experts say it takes a 95% vaccination rate for herd immunity to be established, despite the measles vaccine being one of the most effective ever produced.
In Pennsylvania, measles vaccination rates among children are on the decline. And in many counties, vaccination rates among the youngest school-aged children are below 95%, the target for herd immunity, according to the most recent available Dept. of Health data from the 2023-2024 school year. Only 23 of the 67 counties had a vaccination rate at or over that level among kindergarten students. Measles vaccination rates among kindergarteners were measured as low as 84% in Cameron County.
"In Pennsylvania itself, when we take a look at childhood immunizations for measles, we're somewhere around 93% and 94% statewide, which isn't bad, but it isn't what's considered herd immunity," said Dr. Jeffrey Jahre, an infectious disease specialist at St. Luke's University Hospital in Bethlehem. He was referring to the rate among kindergarten students. "But what's particularly important is we know that (vaccination rates) can vary dramatically from one community to another, and from one county to another."
According to the Centers for Disease Control, roughly 1 in 5 unvaccinated people who catch measles will be hospitalized. One in 1000 infected children will develop encephalitis, an infection that causes inflammation of the brain. And roughly 1 to 3 in 1,000 children will die.
"People now have forgotten about how bad it can really be," Jahre said. "One of the things that becomes very, very evident when you look at the cases that have occurred in the United States is that nearly all have been in unvaccinated people."
This year, 97% of cases in the U.S. have been in unvaccinated people or people with unknown vaccination status.
In a statement, Mark O'Neill, a state Department of Health spokesman, said, "There is no immediate risk to the general public at this time, as the latest school immunization report (2023-2024) shows that 97% of 12th grade students, 95.7% of 7th grade students, and 94% of kindergarten students in Pennsylvania are vaccinated against the measles virus."
"Getting vaccinated is the best way to protect against measles, and residents can request a vaccine from their health care provider," he added.
Here are the vaccination rates in five counties in Southeastern Pennsylvania:
| Bucks | Chester | Delaware | Montgomery | Philadelphia | |
| Kindergarten | 94.59% | 94.7% | 94.18% | 95.21% | 94.46% |
| 7th Grade | 96.57% | 96.17% | 96.13% | 97.85% | 97.49% |
| 12th Grade | 97.38% | 97.57% | 98.2% | 97.98% | 97.14% |
Where is the risk and what can you do?
So far, there has yet to be a confirmed measles case in any of Pennsylvania's highest-risk counties, based on vaccination rates. Those include Cameron County, which has an 84.2% Measles, Mumps and Rubella (MMR) vaccination rate among kindergarten students, but 100% in both 7th and 12th grade; and Pike County, which has an 86.8% vaccination rate among kindergarteners, a 92.7% rate among 7th graders and a 95.7% rate among 12th graders.
But even in a community at or near the herd immunity target of 95% vaccination, a single case can be disruptive.
Take the latest case in Erie County, for example. The county has a 94.9% vaccination rate among kindergarteners, and was above the 95% target among 7th and 12th graders. But the one case in an unvaccinated child led to potential exposures at a gym, Fitness U; a walk-in clinic, UPMC Children's Express; as well as Creative Learning Childcare, which was attended by children under the age of one who are typically not yet vaccinated.
Davis, the Erie county executive, said unvaccinated people who may have been exposed were asked to quarantine. And because the disease can go undetected in infected people for over a week, children under the age of 1, and anyone unvaccinated, are being asked to stay away from Creative Learning Childcare.
"There could be the potential for the community to have a very large struggle, not just having the measles, but quarantining," Davis said. "We know how disruptive that can be to a work schedule, particularly for people who can't afford childcare."
Erie County has an advantage of being one of seven counties to have its own health department, and another four have municipal health departments. Nearly half of Pennsylvania's population lives in these areas, and each of the counties had a measles vaccination rate above 94% in kindergarten students.
Davis said the health department "makes us more nimble." The case was diagnosed on a Sunday, and they were still able to have roughly 20 staff working on contact tracing and other response tasks that day.
Measles symptoms include a high fever, cough, rash, red watery eyes and a runny nose.
"Obviously, we are preparing for the potential of something larger," Davis said. "There's not a major panic, it's just more or less trying to get ahead of any event."
The case in Erie County is a reminder that highly vaccinated counties can still experience measles outbreaks.
"We kind of break (vaccination rates) down county by county, but we see people travel across counties all the time," said Dr. Patrick Gavigan, an infectious disease expert at Penn State Health in Hershey. "People are so connected, so it's easy for cases to spread."
Dauphin County, where Gavigan works, only has an 88.9% MMR vaccination rate among kindergarten students, a 92.5% rate among 7th grade students, and a 95% rate among 12th graders.
It's 1 of 8 counties with a kindergarten measles vaccination rate below 90%, and 1 of 45 with a rate below the 95% herd immunity target.
Pennsylvania also has seven counties where 7th grade MMR vaccination rates are below 90% and 25 below 95%. Among 12th graders, only one county, Tioga, had a vaccination rate below 90%.
"The lower that number gets, the higher the risk for outbreaks and spread," Gavigan said. Though Gavigan cautioned that grade-wide measurements are not necessarily indicative of community vaccination rates, which are the most important factors.
Still, Gavigan says that most parents, even in such areas, shouldn't be worried about their children. "They can get their children vaccinated and feel very comfortable that they're going to prevent infection and serious disease," he said.
But his concern lies with the parents of infants, and for people who are immunocompromised. Cancer patients, for example, often have their immune systems weakened by chemotherapy and other treatments, and can be prone to infection even if they've been vaccinated.
Gavigan said parents of infants in areas with low measles vaccination rates can consider vaccinating their children as young as 6 months old. While the recommended age to vaccinate children is 1, there is no harm in vaccinating a child early. However, antibodies passed down from a vaccinated mother may still exist in the child, which could potentially make the vaccine less effective. But, Gavigan cautioned, no one should make that division without consulting with their pediatrician.
"Herd immunity is so important to the 3% to 5% of kids who don't respond to the measles vaccine, and to that group that is not able to get vaccinated or is immunosuppressed," Gavigan said. "It's one of the most effective vaccines we have."
'We've created this situation'
There is no cure for measles. And the only effective way to prevent the disease is with a vaccine. However, measles vaccination rates have been declining for several years, both in Pennsylvania and the U.S. more broadly.
"In some ways, low vaccination rates are almost a product of the success of vaccines, because no one sees measles," Gavigan said. "So the need for vaccines becomes less apparent to most people. There's also been more spread of misinformation surrounding vaccines. And then I think the COVID pandemic itself disrupted a lot of regular medical visits."
Dr. Jahre attributed the drop in vaccination rates among children to the politicization of vaccines.
"We've created this situation," Jahre said. "COVID was one of the first situations where health information and vaccinations became a political football, and it still is to this day."
But Jahre said the U.S. Health agencies and officials who led the COVID-19 pandemic response are not blameless.
"There was a lot of information that was put out that was said to be absolute when it shouldn't have been," Jahre said. "There was a failure, in some cases, to admit what wasn't known, and an effort to make things sound like one-size-fits-all. When you do that, and you have this discordance, people end up saying, 'I don't know what to believe.'"
Jahre pointed to a string of high-profile communication failures during the pandemic. That included conflicting statements about the effectiveness of masking in preventing COVID-19, and overstatements of the effectiveness of the mRNA vaccines in preventing the disease.
On the flip side, Jahre said, the current U.S. Secretary of Health, Robert F. Kennedy, a long-time leader in the anti-vaccine movement, has overemphasized the risks of vaccinations, and has a history of amplifying misinformation and casting doubt on their effectiveness.
"Recently he did come out and say that your best bet to prevent measles is to get the vaccine, Jahre said. "But he needs to say it loudly, clearly, repetitively, and try to mitigate some of the information that he gave before, which in a lot of cases, was just provocative and not necessarily true."
Kennedy has downplayed the severity of the ongoing measles outbreak and has advocated for unproven and sometimes dangerous treatments. While he has encouraged people to get the MMR vaccine, in an interview on Fox News, Kennedy falsely suggested the vaccine does not provide lifetime immunity and warned it "causes all the illnesses that measles itself causes."
The measles vaccine is between 95% and 97% effective, and vaccinated people who do catch the disease, are far less likely to develop complications. While there have been rare cases of febrile seizures linked to the MMR vaccine, they are unlikely to cause long-term health impacts and there is a far lower risk of complication from the vaccine than the disease itself. There have been no deaths in healthy children linked to properly administered MMR vaccines, according to the Infectious Disease Society of America, a collective of 13,000 doctors and infectious disease experts.
Children who develop measles have a far greater risk of serious complications, and face a 1 to 3 in 1,000 chance of dying.
In Pennsylvania, the statewide rate of MMR vaccination among kindergarteners dipped below the 95% herd immunity threshold in the 2022-2023 school year, dropping to 94%.That was down from 95.1% the previous year, and from over 96% in the 2019-2020 school year, when the COVID pandemic broke out.
While most states allow for religious exemptions to vaccine requirements, Pennsylvania is 1 of 15 that also allows parents to reject vaccines on philosophical or personal grounds. And the rate at which children are claiming those objections has risen.
In the 2020-2021 school year, amid the COVID-19 pandemic, 1.2% of kindergarten students claimed a philosophical exemption to vaccine requirements and 1.2% claimed a religious one. In the 2022-2023 school year those numbers rose to 1.5% and 2.2%, respectively. In 2023, it was 1.8% and 2%.
Jahre believes the law should be changed to get rid of the philosophical exemption.
"We support individual rights," Jahre said. "But when individual rights may infringe on others and create harm, that's where we draw the line."
He compared this to laws requiring car inspections. "It's not just a question of, if your breaks are bad, that you put yourself in harm's way. But obviously, you can then put others in harm's way. The same is true with certain infectious diseases, measles being one of those."
33% of 483 confirmed measles cases in the country, as of March 27, were among children under 5-years-old. Another 42% were among children between 5 and 19-years-old, according to the U.S. Centers for Disease Control.
A quarter of infected children under 5 — 40 out of 157 in total — were hospitalized, and that accounts for half of all measles hospitalizations in the country this year.
"It's frustrating and discouraging, especially with something like measles, where we could have effectively prevented it in the U.S." Gavigan said about the recent cases. "We have something available that is extremely effective and extremely safe. And, as opposed to COVID where it was this new vaccine, we've got years and decades of data to support the effectiveness of this measles vaccine."
Pennsylvania Capital-Star is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. Pennsylvania Capital-Star maintains editorial independence. Contact Editor Tim Lambert for questions: info@penncapital-star.com.