Posts Mislead About Measles, MMR Vaccine Amid Recent Outbreaks

SciCheck Digest

Measles is a highly contagious disease that can be serious and even fatal. Fortunately, it can safely be prevented by vaccination. But in the wake of outbreaks in the U.S. and elsewhere — likely in large part due to low vaccination coverage — social media posts have downplayed the risks of measles and falsely claimed the vaccine “is more dangerous than the actual illness.” 

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Measles is a viral disease that causes a high fever, rash, cough, runny nose, and red and watery eyes. While often mild, the disease can lead to serious complications, including pneumonia and encephalitis, or brain swelling, which can cause deafness and brain damage.

According to the Centers for Disease Control and Prevention, about a fifth of unvaccinated people who contract measles are hospitalized. As many as 1 in 20 kids with measles develop pneumonia; about 1 in 1,000 develop encephalitis, and nearly 1 to 3 in 1,000 die.

Vaccination, in contrast, is almost always effective in preventing measles and typically causes only mild side effects. With the advent of widespread vaccination, measles has become rare in the U.S., usually spreading only when an unvaccinated traveler brings it into the country and encounters enough people who are also unvaccinated or not previously infected. 

That appears to be what happened beginning in December in Philadelphia, when an infant infected overseas was hospitalized and proceeded to infect three other people at the hospital: a baby too young to be vaccinated and an older child and their parent, both of whom were unvaccinated. One child then didn’t isolate and attended a daycare while sick, ultimately leading to infections in five other people. As of mid-January, a total of nine cases have been confirmed in the outbreak, at least six of whom were hospitalized and later released.

Measles cases have also recently popped up in other states, including Georgia and Washington. On Jan. 25, the CDC issued an alert to the nation’s doctors, warning them to be on the lookout for measles symptoms, as a total of 23 confirmed measles cases were reported to the agency between Dec. 1 and Jan. 23. “Most” cases, the CDC said, were “among children and adolescents who had not received a measles-containing vaccine.”

In other parts of the world, the situation is worse. In mid-December, the World Health Organization issued an alert warning of an “alarming” rise in measles cases in the European region in 2023. The latest figures show more than 42,000 measles cases in that region in 2023 — a nearly 45-fold increase over 2022 — including at least five deaths and nearly 21,000 hospitalizations.

As of Jan. 18, an outbreak in a central part of England has grown to 216 confirmed and 103 probable cases, leading U.K. health officials to declare a “national incident” and urge vaccination to stanch the spread.

Health officials and other experts attribute the surge in measles cases to falling vaccination rates, in part due to missed doses during the COVID-19 pandemic, combined with increased travel and fewer public health protections since the pandemic has declined. Because measles is so infectious, the vaccination rate needs to be very high — 95% — to prevent an outbreak in a community.

And yet, in response to news of the recent outbreaks, posts on social media have been rife with misinformation about measles and the main vaccine used to prevent the disease, the measles, mumps and rubella, or MMR, vaccine.

“As the news tries to fear-monger about the measles ‘outbreak’ of 9 whole people, remember that the vaccine is more dangerous than the actual illness,” one Jan. 20 Instagram post incorrectly claimed, likely referring to the Philadelphia outbreak and showing a list of scary-looking adverse reactions pulled from the vaccine’s package insert. “Not to mention, you can actually get measles from the vaccine.”

Another Instagram post focused on the fact that the measles vaccine is a live attenuated vaccine, which uses a weakened virus, to inaccurately suggest the vaccine is an important source of spread of the virus. “The unvaccinated are not the ones you should be concerned with,” the post read, before shifting to minimizing the risks of the disease. “Either way, the measles isn’t something to freak out about.”

Yet another post, accompanied by a clip from “The Brady Bunch,” emphasized the low risk of death from measles in the U.S., while baselessly claiming the MMR vaccine was responsible for the deaths of 450 babies in 2018.

“No one is dying of the measles in the US!!!!!!!” it read, adding, “1 person died from measles in the last 10 years and that person was vaccinated.”

As we’ll explain, there’s nothing to support the 450 number, and it’s unclear what the vaccination status was for the last person who died of measles in the U.S. In any case, focusing just on the lack of measles deaths in America is misleading, since it reflects the success of the vaccine — and fails to account for what would happen if more people forgo the vaccine and outbreaks become more common.

“Get to 1,000 cases a year, and we’ll start to see measles deaths again,” Dr. Paul A. Offit, a pediatrician and vaccine expert at the Children’s Hospital of Philadelphia, told us.

Measles Is Concerning

As we said, contrary to many of the posts that downplay the seriousness of measles, the viral illness can be severe, even if previous generations accepted it as a normal childhood illness.

“Measles is not just ‘a rash,’” a CDC spokesperson told us. According to the agency, before 1963, when the first measles vaccine became available, around 3 million to 4 million Americans were infected each year, 48,000 were hospitalized, 1,000 developed encephalitis and 400 to 500 died.

Most of those deaths, Offit noted, were in previously healthy people. Now, that burden of disease is preventable through vaccination. 

The three big things that landed children in the hospital, Offit said, were dehydration, pneumonia and encephalitis. “If you got chest X-rays on everybody with measles, half would have abnormal chest X-rays,” he added.

“I remember how sick measles could make you back then,” Offit said. “In fact, today, when they ask old people like me to come down to the emergency department to see whether someone has measles, I can usually tell in 30 seconds because they’re sick.”

Very rarely, measles can also cause subacute sclerosing panencephalitis, or SSPE, a fatal neurodegenerative condition that typically manifests some six to eight years after an infection.

Research has also shown that measles can actually wipe out much of the preexisting immunity a person has developed to other germs, which makes them susceptible to other infections for as long as several years after a bout of measles. This does not occur after measles vaccination.

A little girl with measles. Photo by Getty/gdinMika.

Moreover, the reason why even a few cases of measles make the news, and why health officials spring into action to prevent further spread, is because the disease is one of the most contagious diseases — far more so than flu or COVID-19. 

Some 90% of non-immune people will get measles if exposed to an infected person. And direct exposure is not even necessary, since the virus can contaminate surfaces and can linger in the air. 

Speaking of a hospital room after someone with measles has been in it, Offit said, “No one can go in that room for two hours. You have to wait for those small droplets which hang in the air like a ghost to settle.”

It’s worth noting that even today, there are no measles-specific treatments. Doctors can treat the symptoms and provide supportive care, but there are no antivirals that will help someone fight off the virus. The WHO recommends that all people with measles receive vitamin A supplements, as this “restores low vitamin A levels that occur even in well-nourished children,” and can help prevent blindness and possibly death.

MMR Vaccine Highly Effective, Benefits Outweigh Risks

Several of the social media posts cast the MMR vaccine as dangerous by pointing to the long list of adverse reactions in the product insert sheet. 

Offit told us, however, that product inserts really should be viewed as legal documents, not medical communication documents. Just because a reaction is listed doesn’t necessarily mean it has been shown to be definitively caused by a vaccine. The list also doesn’t say how likely a reaction is after vaccination, how severe it might be, or how the risk compares with a measles infection.

For example, SSPE is listed on the MMR sheet, but it’s doubtful that the MMR vaccine can actually cause SSPE. Offit does not think so, and evidence suggests that the few cases reported in people with only a history of vaccination actually reflect instances of unrecognized measles infection. In any case, rates of SSPE have fallen in countries with widespread vaccination, and vaccination is the only way to actually prevent SSPE.

As with any medical product, the MMR vaccine is not 100% safe, but it is remarkably so — and the benefits greatly outweigh the risks. Most people experience no or only mild and expected side effects, such as a sore arm and low-grade fever. About 5% of people will develop a rash, according to the CDC’s Pink Book on vaccines.

More rarely, other side effects can occur, including febrile seizures, which do not cause long-term harm, and a brief decrease in platelets, which has never been fatal. (The rubella component of the MMR vaccine can also cause joint pain and swelling, primarily in adults, but this is also temporary.)

The rash and fever can be viewed as a very mild form of measles, Offit said. But contrary to social media posts that equate this with a natural measles infection, these symptoms are far more mild and do not pose the same risk of complications or viral transmission.

The weakened measles virus in the MMR vaccine is only capable of giving someone a dangerous infection if a person is severely immunocompromised. For this reason, the CDC told us, these people should not be vaccinated.

As we’ve explained before, people vaccinated with live viral vaccines can shed, or release small amounts of the weakened viruses outside of their bodies, but this is expected and not cause for alarm.

Children who develop a rash after a measles vaccine are not considered contagious, and no precautions are necessary, even if they are around immunocompromised people. In fact, to better protect immunocompromised people, who may not be able to be vaccinated, or may not respond fully if they are, the MMR vaccine is explicitly recommended for household contacts of such individuals.

The CDC told us that transmission of the weakened measles virus from someone who received the MMR or MMRV vaccine, which adds a component to protect against chickenpox, “has never been proven,” and cited a 2016 systematic review that included 773 scientific articles. “No evidence of human-to-human transmission of the measles vaccine virus has been reported amongst the thousands of clinical samples genotyped during outbreaks or endemic transmission and individual case studies worldwide,” it concluded.

The agency also said there is “no history” of a measles outbreak ever occurring as a result of the vaccine.

As for the claim that 450 babies died of the MMR vaccine in 2018, the CDC told us there “is no evidence from any of CDC’s vaccine safety monitoring systems to support this claim.” We also could not find any evidence to support this.

In the U.S., the MMR is given in two doses, at 12 to 15 months, and then at 4 to 6 years old. A single dose is about 93% effective in preventing the disease, according to the CDC, while two are about 97% effective. In the unlikely scenario that a vaccinated person does contract measles, the disease is usually milder and less contagious to others than in someone who has not been vaccinated.

Last Measles Death in U.S. Reinforces Need for Vaccination

A post arguing against vaccination pointed to the rarity of measles deaths in America and misleadingly claimed that the single person to die of measles in the U.S. in the last decade was vaccinated.

The CDC confirmed that the last measles death in the U.S. occurred in 2015, but said the person’s vaccination status was unknown. The Seattle Times reported in 2016 that the woman who died “may have been” vaccinated as a kid, but the family did not have evidence of this. So her status was listed as unknown. Regardless, the example is missing important context, because experts said the case underscores the need for more vaccination, not less.

The woman who died was a Washington state resident who had other health conditions and was taking medications that suppressed her immune system. She died of pneumonia, and it was not apparent the pneumonia was due to measles until an autopsy was performed, as she did not have a rash or other symptoms. Immunocompromised patients are known to sometimes lack a rash with measles.

Particularly because the woman had a suppressed immune system, even if she was vaccinated, this is not evidence that vaccination doesn’t work. As multiple experts explained to USA Today in 2015, the death is a prime example of why it’s vitally important for everyone who can get vaccinated to do so, to prevent measles from circulating and posing a risk to vulnerable people who either can’t get vaccinated or for whom vaccination is less likely to be effective.

“This tragic situation illustrates the importance of immunizing as many people as possible to provide a high level of community protection against measles,” the Washington health department said at the time in a statement.

Editor’s note: SciCheck’s articles providing accurate health information and correcting health misinformation are made possible by a grant from the Robert Wood Johnson Foundation. The foundation has no control over’s editorial decisions, and the views expressed in our articles do not necessarily reflect the views of the foundation.


Signs and Symptoms.” Measles (Rubeola) page. CDC. Accessed 29 Jan 2024.

Complications of Measles.” Measles (Rubeola) page. CDC. Accessed 29 Jan 2024.

Vaccine for Measles.” Measles (Rubeola) page. CDC. Accessed 29 Jan 2024.

MMR Vaccine (Measles, Mumps, and Rubella): What You Need to Know.” Vaccine Information Statement. CDC. 6 Aug 2021.

Measles Cases and Outbreaks.” Measles (Rubeola) page. CDC. Accessed 29 Jan 2024.

Gutman, Abraham. “Health department warns of measles cluster among unvaccinated residents that originated with CHOP patient.” Philadelphia Inquirer. 4 Jan 2024.

Health Department Reports Additional Measles Exposures.” Press release. Philadelphia Department of Public Health. 4 Jan 2024.

McDevitt, Charles. “Health department cautions Philadelphians about recent measles cases.” Philadelphia Department of Public Health. Updated 17 Jan 2024.

Gutman, Abraham. “Another person infected with measles at a Northeast day-care center as Philadelphia outbreaks grow to nine cases.” Philadelphia Inquirer. 17 Jan 2024.

DPH Confirms Measles Case in Metro Atlanta.” Press release. Georgia Department of Public Health. 18 Jan 2024.

Health Advisory: Measles Outbreak in Southwest Washington.” Press release. Tacoma-Pierce County Health Department. 19 Jan 2024.

Stay Alert for Measles Cases.” CDC Clinician Outreach and Communication Activity. 25 Jan 2024.

A 30-fold rise of measles cases in 2023 in the WHO European Region warrants urgent action.” Press release. WHO. 14 Dec 2023.

Kazakhstan responds to rapid escalation of measles cases.” Press release. WHO. 23 Jan 2024.

Measles outbreak could spread warns UKHSA Chief Executive.” Press release. UK Health Security Agency. 19 Jan 2024.

Putka, Sophie. “Measles Cases in Several States: What’s Going On?” MedPage Today. 18 Jan 2024.

M-M-R® II (Measles, Mumps, and Rubella Virus Vaccine Live) package insert. FDA. Revised Aug 2023.

Wodi, A. Patricia and Valerie Morelli. “Chapter 1: Principles of Vaccination.” CDC Pink Book. Aug 2021.

Offit, Paul A. Director, Vaccine Education Center, Children’s Hospital of Philadelphia. Phone interview with 24 Jan 2024.

CDC Spokesperson. Email sent to 24 Jan 2024.

Measles History.” Measles (Rubeola) page. CDC. Accessed 29 Jan 2024.

Subacute Sclerosing Panencephalitis.” National Institute of Neurological Disorders and Stroke. Accessed 29 Jan 2024.

Mina, Michael (@michaelmina_lab). “A heartbreaking consequence of lapses in vaccination! A measles outbreak is spreadinf in Philadelphia. MEASLES! It sends kids to the hospital, erases existing immune memory (creating long term risks) and kills 1 in 1000 It was eliminated in the US, but we seem hell bent on reversing that …” X. 8 Jan 2024.

Mina, Michael J. et al. “Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens.” Science. 1 Nov 2019.

Mina, Michael J. et al. “Long-term measles-induced immunomodulation increases overall childhood infectious disease mortality.” Science. 8 May 2015.

Measles.” WHO Fact Sheet. 9 Aug 2023.

Transmission of Measles.” Measles (Rubeola) page. CDC. Accessed 29 Jan 2024.

For Healthcare Providers.” Measles (Rubeola) page. CDC. Accessed 29 Jan 2024.

Subacute sclerosing panencephalitis and measles vaccination.” WHO. Accessed 29 Jan 2024.

McLean, Huong Q. et al. “Prevention of Measles, Rubella, Congenital Rubella Syndrome, and Mumps, 2013: Summary Recommendations of the Advisory Committee on Immunization Practices.” MMWR. 14 Jun 2013. 

Tesini, Brenda L. “Subacute Sclerosing Panencephalitis (SSPE).” Merck Manual Consumer Version. Reviewed/Revised Jun 2023.

Measles, Mumps & Rubella (MMR) Infographic.” CHOP Vaccine Education Center. Accessed 29 Jan 2024.

Vaccine (Shot) for Measles.” CDC. Accessed 29 Jan 2024.

A Look at Each Vaccine: Measles, Mumps and Rubella (MMR) Vaccine.” CHOP. Reviewed 2 Jan 2024.

Gastanaduy, Paul et al. “Chapter 13: Measles.” CDC Pink Book. Aug 2021.

Jaramillo, Catalina. “Vaccine Shedding Is Expected With Some Vaccines and Generally Not Harmful, Contrary to Post.” 12 Dec 2023.

Altered Immunocompetence: General Best Practice Guidelines for Immunization.” CDC. Updated 1 Aug 2023.

Greenwood, Kathryn P. “A systematic review of human-to-human transmission of measles vaccine virus.” Vaccine. 12 Apr 2016.

Measles, Mumps, and Rubella (MMR) Vaccination: What Everyone Should Know.” CDC. Accessed 29 Jan 2024.

Aleccia, JoNel. “Fatal measles case linked to exposure at tribal clinic, records show.” Seattle Times. 19 Feb 2016.

Szabo, Liz. “Measles kills first patient in 12 years.” USA Today. 2 Jul 2015.

Measles led to death of Clallam Co. woman; first in US in a dozen years.” Press release. Washington State Department of Health. 2 Jul 2015.

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