This past month, Pennsylvania reported four measles-associated deaths, including two babies who were too young to receive the MMR vaccine. These are the first measles-associated deaths reported in Pennsylvania in 35 years.

These are the first measles deaths in Pennsylvania in 35 years.  The state now has reported about 700 cases this year, and the CDC has confirmed over 3,200 cases across the country.

I have been a pediatrician long enough to maintain my composure when reading difficult headlines about public health, but this particular headline managed to sneak past my normal filter. Instead of giving you a clinical analysis of the situation, I want to take the time to explain why such deaths have such a heavy impact on us who work in pediatrics, and what I hope families take away from this situation. It is normal to feel disheartened, but feeling disheartened without any clear direction doesn’t offer anyone any protection.

Some diseases humble us in medicine, especially when we don’t have effective tools to combat them.  Measles is not one of those diseases.

Measles is one of the most contagious viruses we know of.  If one person has the virus, up to 9 or 10 unprotected people can get it from coming in contact with that person.  The virus can remain in the air of a room for up to 2 hours after the infected person has left.  It is not necessary to come into physical contact with the infected person to catch the disease; you simply have to breathe the same air they breathed.

On the other hand, there is one of the most effective vaccines that has ever been developed.  Two doses of the MMR vaccine is about 97% effective at preventing measles.  To put this into perspective, we think of a “good” flu vaccine year as having 40-60% effectiveness, and even though this isn’t close to 100%, we still recommend it since it still stops hospitalizations and deaths.  The measles vaccine is in a different category.  Because it is so effective, in 2000 the United States declared that measles had been eliminated, meaning that the virus was no longer being transmitted continuously here.

And we can see that protection playing out in the current Pennsylvania outbreak. As of September 18, Pennsylvania had reported 767 measles cases. Only four, less than 1%, were in people considered appropriately vaccinated for their age.

That is the reason why these deaths hit differently than the deaths caused by illnesses that we are not yet able to prevent effectively.

Before we go any further, I want to be very clear about what we actually know about these four deaths, because I don't want to use tragedy to make a point the facts don't support.

An 18-year-old died from acute disseminated encephalomyelitis, a rare and severe neurological complication of measles. The Mifflin County coroner determined measles was the cause of the complication and death. A 40-year-old woman with underlying respiratory disease died from respiratory failure. Her death certificate included probable measles along with COPD and asthma as underlying causes. Pennsylvania later completed its investigation and classified her death as measles-associated. The circumstances of the two infant deaths are different from each other. A newborn contracted measles in utero and died shortly after birth from a ruptured spleen. The Lancaster County coroner reported that an autopsy found the spleen was not enlarged or inflamed and concluded that measles did not cause the fatal splenic injury. Pennsylvania's Department of Health separately investigated the case and classified the newborn's death as measles-associated.

The second infant was 6 weeks old and had a rare genetic disorder called Amish lethal microcephaly that made her medically vulnerable. No autopsy was performed, but the Lancaster County coroner reported that she had contracted measles and determined that measles caused her death.

Both infants were too young to receive the MMR vaccine.

And I know what some people will say: "But did they die FROM measles or WITH measles?"

Listen, details matter. I care about those details too. But measles did not help the situation. In these four deaths, it either caused or contributed to the illness that led to death. This wasn't someone who happened to test positive for measles while dying from something completely unrelated.

So we can spend our time debating "from" versus "with," or we can focus on reducing the risk of measles in the first place with a vaccine that is about 97% effective after two doses.

I know where I'm putting my energy.

I talk about misinformation so much because I have seen the effects it has on families sitting opposite me in an examination room.  However, I would like to be careful when telling this story because we don’t know the personal circumstances of the four people who died, and I don’t want to write their stories for them.

What we do know is that this outbreak has been concentrated in Lancaster County, a region which hosts large communities of Amish and Mennonite families.  Among these groups of people, vaccination rates have always been low.  In many of these families, the decline in vaccination is not so much due to a viral post but because of a long-established custom and lack of access to medical care.

That distinction matters to me.  I have not and will never shame anyone into making a decision.  My aim has always been to enable each family to reach their own conclusions after having obtained accurate information about the effects of diseases and the effects of vaccines.  If a person chooses not to get a vaccine because they came across a false claim on the internet, then that is a failure on our part in our information environment.  If someone refuses a vaccine because their community had never been properly engaged with reliable information, then that is a failure of connection.  We can address both issues.

And people are working on these issues.  The Department of Health of Pennsylvania has been operating mobile clinics in Lancaster County and has administered over 600 doses of the MMR vaccine since late April.  Compare that to the 179 doses given in the entire county over the last year.  Public health initiatives depend heavily on relationships, and it takes time to build those relationships.

What is disheartening is that the science in question is part of humanity’s biggest achievements.  A virus which had once infected almost every child in the world has been reduced to the point of near extinction in this country within just a few decades. Families have a right to accurate information when making their decision, and too many are instead hearing a distorted account of it. 

I can respect a family’s right to make a choice even though I grieve over what occurs when the information from which that choice is based on is incorrect.

I want to add one more layer here, because it matters just as much as the outbreak itself. Some of the most convincing misinformation about vaccines right now is not coming from a random corner of the internet. It is coming from people with real medical credentials.

I don't normally call out fellow educators in this newsletter, but I have sat back and watched this person do this for years. She is a nurse who has built a large following by leading with faith and warmth, telling parents to trust their gut. She comes across as caring, and I believe she thinks she is helping. Caring does not make a claim true, though, and a warm delivery under the veil of being a god-loving human does not make bad information safer.

In the middle of the worst measles year we have seen in decades, she has claimed that children between 16 and 24 months are at higher risk of side effects from the MMR vaccine, and that vaccines should be separated instead of given together.

But where is the evidence for that?

The first MMR dose is routinely given around 12 to 15 months, with the second typically given between 4 and 6 years. There is a small known risk of febrile seizure after MMR, about 1 in 3,000 to 4,000 children vaccinated, but there is no recommendation to avoid MMR between 16 and 24 months because that age somehow makes the vaccine unsafe. And there is no evidence that splitting the MMR vaccine into separate measles, mumps, and rubella shots makes it safer. Delaying vaccines simply means delaying protection.

What is the purpose of putting information like this out there without evidence to support it? We are part of the same medical community. I care about patients just as much as she says she does. If good evidence showed that we needed to change when or how we vaccinate children, I would want to know that too. Our recommendations should change when the evidence tells us they should.

None of this means a parent who is scared or unsure is doing something wrong by asking questions. It means that when someone with a medical license tells a frightened parent something that isn’t supported by research and leans on that license as a reason to trust it, that carries a different kind of weight than a stranger’s opinion online.

I am also a person of faith who leads with compassion when I sit across from a parent, and I have spent over 11 years watching what happens when a disease we know how to stop is allowed back into a community. My concern was never about a family choosing something different than I would choose. It is about a family making that choice off information that simply is not true. Informed choice only works when the information part holds up. Take that away, and it stops being a choice and instead a misguided decision.

Neither of the babies who died was old enough to receive the MMR vaccine. And this is where community matters.

Babies this young may have some protection from antibodies passed to them during pregnancy, but that protection varies and can fade quickly. Until they're old enough to be vaccinated, part of their protection depends on how much measles is circulating around them.

I think about this every time I walk into a pediatric waiting room. The 3-day-old baby who is there for a weight check may be sitting twenty feet away from another patient who came in that same day.

When community vaccination rates are high, there is an added layer of protection because measles has fewer opportunities to spread. This matters especially with measles because it is one of the most contagious infections we know of. One person with measles can infect up to 9 out of 10 unprotected people around them, which is why roughly 95% population immunity is needed to prevent sustained spread. When vaccination rates fall below that level, measles can find pockets of susceptible people quickly, and our youngest and most medically vulnerable patients are among those who can't protect themselves through vaccination.

The MMR vaccination rate among kindergarteners in Lancaster County is about 88.5%.  Across the country, the rate of vaccination has declined, and last school year vaccine exemptions among kindergarteners reached a record 4.2%.  Vaccines have always been a personal and a collective matter, although patients’ records are individual; immunity from measles remains a project that involves the whole community.

Elimination is a term with a definite meaning.  It does not imply zero cases; rather, it means that there has been no continuous chain of viral spread in the country for a period of 12 months or more.  As I already stated, the United States achieved this status in 2000 as a result of many decades of vaccination work and then maintained this status for a quarter of a century by picking up cases and containing them quickly.

The streak is obviously in real danger.  The entire Americas region has already lost its elimination status in November 2025 following a Canadian outbreak that reached a 12-month threshold.  The review of the United States’ status is due in November 2026, and the researcher who is leading the review committee has publicly stated that Utah’s ongoing outbreak seems to have lasted for more than a year, which is the primary criterion for losing elimination status.

So why should any of this label talk matter to a parent? The status of elimination indicates that the population is well protected so that outbreaks die quickly.  If that status is lost, then the virus has found enough people who are not protected and therefore can continue to spread indefinitely.  In other words, this means that there will be more contact with those who have measles in waiting rooms, more quarantines in schools and childcare facilities, more infants requiring emergency protective treatment following an exposure, and more families who will have to find out for themselves about the complications such as pneumonia and brain inflammation.

And the road back to elimination status is long.  A country must again demonstrate that each chain of transmission has been broken for a full year, which in turn means having high vaccination coverage again in nearly every community. 

I promised you this wouldn’t just be grief on paper, so what can you do now?

Look at your child’s MMR record.  The AAP vaccine schedule calls for the first vaccine to be given when your child is 12-15 months old and the second dose between 4-6 years old.  In the case of an outbreak or when traveling to a place with higher measles cases, the second dose can be given as soon as 28 days after the first dose. 

If your baby is between 6-11 months old and you live in or are going to an area where there is an outbreak, you can ask about receiving an early MMR dose.  The Health Department of Pennsylvania is currently recommending this for infants in affected countries, and the CDC has long advised it for international travel.  The early dose offers moderate protection during the period when there is high risk, but your child will still have to have the two scheduled doses later on, as the early one does not count as part of the vaccine series.

If you have a baby who can’t be vaccinated yet or a toddler who is not fully vaccinated due to age; the people nearby need to provide the protection.  Make sure that the adults and older children in your child’s immediate circle have immunity.  If you live in an area that is experiencing an active outbreak, be more selective about spending time in crowded indoor places.  You don’t need to avoid the world, but you should exercise caution.

If anyone in your family shows signs of measles such as having a fever, cough, runny nose, red, watery eyes, and a rash, call your doctor before heading anywhere.  Making that phone call allows staff to look after other people in the waiting room, including newborns.

I don't want to pretend that this newsletter has a tidy ending. Four families in Pennsylvania are going through the sorrow of losing someone they love. And beyond the deaths are countless other lives being affected by measles right now. Children getting sick. Families ending up in the hospital. Babies and immunocompromised people being exposed. Families having to quarantine, miss school, miss work, and worry about whether someone they love will get sick next.

But I also won't let feeling disheartened turn into feeling defeated.

So I’ll come back with the two questions that I always ask: what does the evidence show, and what has my clinical experience showed me? 

Measles is one of the most preventable serious diseases we have, and the vaccine remains one of the major achievements of modern medicine. The benefits of vaccination far outweigh the known risks. And in my clinical experience, I have seen that the vast majority of parents deeply love their children and want to protect them. When they're given accurate information, offered a real conversation, and have genuine access to vaccines, the majority choose to vaccinate their children.

And right now, we need to make sure our children are vaccinated on schedule, especially for a vaccine as effective as measles. Vaccination protects the child getting the vaccine, but it also helps protect the newborn who is too young for their first dose, the child who can't be vaccinated for medical reasons, and the person whose immune system may not respond as well to vaccination. With a virus as contagious as measles, our choices affect the people around us too.

 And please be thoughtful about where you're getting your health information. Follow creators, including medical creators, who are willing to talk about the facts, the benefits AND the risks, and who can show you the evidence behind what they're saying. Be cautious when someone makes a scary claim without showing you where it came from.

If you still have questions about vaccines, I have a free vaccine guide that walks through the benefits, known risks, common side effects, and many of the questions I hear from parents in my own practice. My goal isn't for you to blindly trust me. It's for you to have accurate information so you can make informed decisions for your family.

The vaccine didn’t fail us this year. We are at risk of failing the vaccine.

If you’ve had a conversation about measles vaccination within your own family or community, in either direction, what helped it stay respectful? Hit reply and tell me.

Dr. Mona

Dr. Mona will answer these questions in a future Sunday Morning Q&A email. Chances are if you have a parenting concern or question, another parent can relate. So let's figure this out together!