Many of us never thought we would see measles outbreaks in the United States (U.S.) like this again. Measles was declared eliminated in the U.S. in 2000. However, since the beginning of 2025, there have been over 3300 cases of measles across the United States1. The highest number of cases seen in over 30 years3. Unfortunately, deaths due to measles have also been reported.2,3
Reference: Johns Hopkins Univ Measles Tracker, accessed online 9/13/26
The good news is that measles can be prevented – by getting vaccinated. We will discuss this in more detail shortly.
Unfortunately, the majority of those who contracted measles in the U.S. in 2026 were not previously vaccinated1,2, which could have protected them against measles. Some of these unfortunately had no choice; they were babies who were too young to get the measles vaccine (under 12 months old). Babies rely on the rest of us to be vaccinated and keep them safe.
Measles is caused by a virus. It is one of the most contagious infections. It spreads through the air when a person infected with measles coughs or sneezes. The droplets land on surfaces, and someone nearby inhales (breathes in) the infected droplets. It can also be spread by direct contact with fluids from the nose or mouth of someone who is infected with measles. It is so contagious that if one person has it in a room, 9 out of 10 people around that person will also become infected if they are not protected (vaccinated). 2 The measles virus can remain infectious in the air for up to 2 hours after an infected person leaves an area.
What does it mean when we say ‘immune or protected’ from measles?
It means that you are already immune to or protected from measles. This can mean that you either received your recommended measles vaccination in the past or had measles disease when you were younger, so you are now immune.
Your immune system makes memory cells after infections. Vaccines can also stimulate the making of memory cells (see section below on how Vaccines work). These memory cells, whether from infection or vaccination, remember the germ. If your child is exposed to the germ in the future, their memory cells can quickly make antibodies (fighting cells) to keep them from getting infected.
Most people born in the U.S. before 1957 are immune to measles (meaning they either had measles as children or were exposed to measles and developed protective antibodies). However, it is always safer to find out if you are immune:
Measles symptoms typically start to appear 7 to 14 days after being in contact with the virus. Measles infection starts with a high fever (may get as high as 104 degrees F), cough, runny nose, and red, watery eyes. Next, people with measles develop red/brownish flat spots that become bumpy and blotchy. The rash starts on the face and then spreads down the body. The rash usually shows up about 3-4 days after the other symptoms begin. This means a person can be contagious and spread measles to someone else even before they know they have it. The contagious period typically lasts from 4 days before the rash appears until 4 days after it shows up.2,3
Visit https://www.cdc.gov/measles/signs-symptoms/photos.html for pictures of how measles looks.
Yes. It surely is. It can have lots of severe complications.
Kids who get measles may develop mild infections like diarrhea or an ear infection, but more serious infections can happen, like pneumonia. 1 out of every 20 kids who get measles may develop pneumonia. This pneumonia can be very serious and may lead to death. Children who have a weakened immune system, like cancer, are more susceptible to getting very sick from measles.
Remember, measles is caused by a virus. It is not like strep throat, which is caused by bacteria and can be treated with an antibiotic so it goes away. There is no medicine or antiviral to cure measles. Doctors will try to give you supportive care, like fluids to keep you hydrated and other medications to help keep you stable until your body heals.4
What is scary is that some kids develop a condition called SSPE, subacute sclerosing panencephalitis. It is rare but deadly. 7 to 10 years after having measles, the virus that has been hiding in the body starts to attack the nervous system, and the child’s brain begins to deteriorate, eventually leading to death.2,3
Adults can get measles also. It is not a disease we see in kids only.
Unfortunately, about 1 out of every 1000 people infected with measles will die even with the best of care.
Another disturbing complication from measles is something called immune amnesia7.
This means the measles virus causes your immune system to forget how to fight infections. Immune amnesia occurs only after a measles infection. It is not caused by the measles vaccine. The measles virus can wipe out immune memory—memory of other harmful viruses and bacteria. This side effect, known as immune amnesia, can affect anyone who gets measles. It happens when the measles virus attacks the memory cells in the immune system.
The measles virus can find and destroy helpful memory cells. This immune amnesia can erase up to 73% of your child's immune memory. When some or all of the memory cells are gone, it becomes harder for your child's immune system to remember germs and fight off infections. Your child will still be immune to measles, but immunity to other diseases will be lower. Vaccines and new infections are the only ways to restore this immunity.
Quote: Healthychildren.org5 “Despite billions of life-saving vaccines given worldwide, disinformation continues to spread. Routine vaccination rates have dropped to dangerous levels. Measles outbreaks have surged, spreading within schools and communities where false claims have led some parents to refuse vaccines for their children”.
One reason that we are seeing more of these outbreaks is that we have many people in the U.S. now who are not vaccinated and protected from measles, and so they can spread it to others in their community who are also not vaccinated. The reason we could say in 2000 that measles was eliminated was because we had so many people vaccinated and because we had protocols in place, like school entry guidelines, travel guidelines, and more, that were being closely monitored to ensure that we were keeping our communities safe from these deadly diseases. Thanks to vaccines, we no longer see diseases like polio, tetanus, or chickenpox in our communities. Before the measles vaccine was available in the U.S., each year, an average of 450 people died from measles; most of them were previously healthy children. Thanks to the measles vaccine, we can now protect children from measles.
There is something called community (herd) immunity. Community immunity happens when enough people in a community are protected from a contagious disease through vaccination or previous illness (getting vaccinated is always safer), so the disease can’t spread easily. When you reduce the number of people who are susceptible to infection, you limit the ability of the disease to spread. Community immunity protects those who cannot be vaccinated, like newborns or people with certain medical conditions.6
From: Voices for Vaccines: https://www.voicesforvaccines.org/content/uploads/2026/04/Community-Immunity-26.pdf
For diseases like measles and whooping cough, we consider a 92-95% 10 vaccination rate in a community as the threshold to say, okay, now we have community immunity.
But let’s talk about measles vaccination rates. Recent data show that in many states, those rates have fallen to 91-92% in some communities, not the 92-95% needed to provide us with community immunity. MMR vaccine coverage among kindergartners was 92.4% in the 2025–2026 school year 2, meaning more than a quarter of a million children, 280,000 in the U.S., started kindergarten in the 2025-26 school year without protection from the MMR vaccine.
So now those kindergarteners are at risk of contracting and spreading measles, and many people in their community who are not vaccinated may be at risk as well. For example, other kids in the classroom with weaker immune systems may be sitting next to unvaccinated children (e.g., a child with sickle cell disease or a child with cancer who has just finished chemo/radiation treatment). These more vulnerable children are also at risk of contracting measles, even if they had their measles vaccines in the past.
Also, the earliest age you can get the measles vaccine is 1 year (12 months) old. So, if babies under a year old come into contact with someone with measles, they are very likely to get it. As of September 11, 2026, there is an ongoing measles outbreak linked to a metro Atlanta daycare. https://dph.georgia.gov/press-releases/2026-09-11/dph-measles-update
Remember, choosing not to vaccinate children leaves them vulnerable to measles but also increases the risk of exposing others around them to the measles virus.
Make sure that all children have received their MMR vaccine.
Adults - try to locate your vaccine records and make sure you have a record of having had a measles vaccine. If you were born in the US prior to 1957, you are probably immune. If you are not sure, or cannot find those records, then talk to your healthcare provider right away. They will advise you on whether to get a blood test to see if you are immune, or they may give you an MMR shot now to protect you.
If you live in an outbreak area, additional doses of the MMR vaccine may be recommended.
If you are traveling internationally, make sure everyone traveling has a record of having had their MMR vaccine.
Note: Measles is a live (but weakened) vaccine, so children with immune problems or who take medications that suppress the immune system should not receive the measles vaccine.5. Their doctor will advise on the best options to protect them.
The MMR vaccine and all other vaccines may be obtained at:
Remember, always ask!! Do not let fear of potential costs be a factor.
Nothing, no medicine (not even aspirin), no vaccine is 100% safe. There may always be a side effect or a reaction. Luckily, most side effects are very mild (sore arm, 1 to 2 days of fever/chills, mild swelling) in the area where you got the shot. Serious side effects are extremely rare.
These mild side effects are expected. They are very common. These are signs that your immune system is reacting to what it thinks is a germ when you get vaccinated. Your immune system sees the vaccine as something foreign to your body and tries to get rid of it – that’s why you get the fever/chills, the sore arm, and so forth. (Please note that there are some people who don’t have any of these side effects and their immune system is still working; it just depends on the person).
These mild side effects are easily treated, for example, by massaging the area with a warm, wet towel, or by taking medicines to reduce your fever or pain. Always check with your healthcare provider first to see which fever/pain-reducing medicine is the right one for you, based on your health conditions and age.
The risk of the disease itself and complications from the disease is far greater and far more common than serious reactions from vaccines.
Remember, the mild side effects we experience are what babies go through when they get their shots. We are much older now, so of course we don’t remember what it was like when we got our shots as babies. These mild side effects after getting shots are normal and expected. It is NOT a sign that you have the disease or got sick from the vaccine. A vaccine does not cause disease. If the virus or bacteria is used as an ingredient in the vaccine, it is either not alive, or it is very, very weak and cannot cause the disease it is meant to protect you from.
By the way, many people don't get the flu shot now because they may have had redness, swelling, a sore arm, or a fever after getting the flu shot in the past. Now you can tell them that these reactions were probably normal and were expected side effects, and advise them to keep getting the flu shot every year to protect themselves and their families from the flu.
Well, as we enter the flu and cold season, remember to get your:
There are other vaccines your family needs as well:
Vaccines for Babies, Toddlers, Children and Teens:
Childhood and Teen Vaccines: See the recommended childhood vaccine schedule from the American Academy of Pediatrics (AAP, at https://www.healthychildren.org/English/safety-prevention/immunizations/Pages/Recommended-Immunization-Schedules.aspx.
Adults need shots too – not just children: There are vaccines to protect you from shingles, pneumonia, tetanus, meningitis, polio, RSV (respiratory syncytial virus), and many other diseases.
Follow the Adult vaccine schedule from the American Academy of Family Physicians (AAFP) at https://www.aafp.org/clinical-insights/immunizations-and-vaccines/immunizations-schedules-resources/adult-immunization-schedules.
Remember, vaccines protect you as an individual, but they also keep our communities safe. Some people cannot get a vaccine because of their health condition, or even if they do get vaccinated, their immune system is weak, so they rely on all of us to help protect them.
Encourage your family and friends to all get vaccinated.
Healthcare provider (doctor, nurse, physician assistant/PA, nurse practitioner/NP) – someone who can diagnose and treat your medical condition.
Immune to infection/disease: To be immune means your body is protected or resistant to a specific disease or harmful germ so that it cannot make you sick. You are no longer susceptible to that disease.
Antibodies: substances that protect you against a germ. Your immune system makes antibodies when it comes into contact with a germ, or something that appears foreign to the body, like a vaccine shot. Antibodies protect your body. Some of the antibodies are called memory cells – they stick around in your body after you get infected with a germ, so that next time you come in contact with that germ, you are armed and ready to fight off the germ.
What is a vaccine? How do vaccines work?
There are many types of vaccines. Some vaccines include a weakened or killed piece of the germ it is trying to protect you from. Remember: if the germ (virus or bacteria) is used as an ingredient in the vaccine, it has first been killed; it is not alive, or it has been made very, very weak.
“Vaccines have active ingredients that give information to your child's immune system, so it knows how to create its own antibodies. Here's how that works. Just like a child learns to read, their immune system learns, too. A vaccine is like a book that teaches the immune system to recognize and resist a disease. All it takes is a tiny amount of active ingredients in each vaccine for the immune system to understand and remember what to do when it sees the actual virus or bacteria .8
When you receive a vaccine, your immune system sees the vaccine as something that should not be in your body. Remember, the vaccine may contain a killed piece of the germ or an extremely weakened piece of the germ. Your immune system says, “This should not be here,” and it makes antibodies and memory cells. This way, in the future, if your body comes into contact with the real germ the vaccine is protecting you from, your body recognizes it and is armed and ready to protect you. Now, you are less likely to get the infection, or if you do get infected, it will not make you as sick.
There are some vaccines that use a live, weakened virus. This type of vaccine can very rarely cause disease in people with illnesses that affect their immune system, such as cancer, or who require medicine that affects their immune system. Because of this, their doctor may instead provide a different form of the vaccine or advise them not to get that vaccine.
Here are a couple of short videos describing how vaccines work; visit:
the American Academy of Pediatrics: https://www.youtube.com/watch?v=l8fewK2Vxes and from PBS: https://www.pbs.org/video/nova-immunity-and-vaccines-explained/
References
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