By: Robert W. Frenck, Jr., MD, FAAP
Yes. Vaccines are safe for children and are carefully tested and monitored.
Most vaccine fears come from misinformation, not science. Read on to learn why online rumors can’t be trusted and the truth behind some of the most popular myths about vaccines.
It’s natural to look online for guidance about important health decisions. Parents want to understand the risks and benefits of vaccines for children. Sadly, there is so much information online that search results are often a mix of rumors, half-truths and only a small number of reliable, science-backed resources.
Information about vaccines parents find online is often false and scary. It can make them second guess the facts they hear from pediatricians. It also pushes parents away from vaccines that have kept children healthy for decades. How do you navigate this sea of misinformation?
Why does vaccine misinformation spread so easily online?
Online rumors about vaccines are not fact-checked
Fact-checking means confirming if information is true. It looks at who created and shared the information, why they posted it, and what evidence they have to support it.
Fact-checking also involves seeing what trusted experts have said about the topic.
Most information about vaccines that scares parents has not been fact-checked. That means no one verified where it comes from and whether it is real before posting.
This is why online rumors about vaccines are not a good source of information to make decisions about your child’s vaccines.
Posts look authentic but they are not
Many times, posts with false information about vaccines look authentic. They have catchy images and seem to come from people who know a lot.
People posting may say they are doctors or are posting what "doctors say." But saying you are a doctor or talking about studies doesn’t mean they really know about vaccines. It can’t replace what actual experts on health and vaccines know.
Some people say they belong to an organization with a medical or scientific sounding name. But often no board-certified doctor or qualified scientist belongs to it.
False information can also be visually appealing. Well-designed posts, with images or videos that catch our attention, can still be misleading or completely wrong.
Algorithms promote emotional reactions, not facts
Social media algorithms are meant to catch people’s attention and keep them engaged as long as possible. They promote posts that are attractive to a lot of people and get strong reactions. That usually means posts that spark fear or outrage—not facts.
When you click on or interact with even a single misleading post, the platform is likely to show you more content like that. Over time, you can be pulled into a disinformation "rabbit hole" without even realizing it.
You may be surprised to know that the "anti-vaccine" content on social media platforms originated from a tiny group of just 12 people. In a 2021 report, the
Center for Countering Digital Hate found that this tiny group—it nicknamed
the "disinformation dozen"—was the original source of about two-thirds of the anti-vaccine posts and messages. These 12 individuals spread misinformation to attract attention and drive traffic to their own websites—not to help parents make informed decisions
Common vaccine myths & the facts behind them
Over the years, many myths about vaccines have spread online. Here is a look at some of the most popular: where they came from and why they are not true.
Vaccines & autism spectrum disorder (ASD)
How did the myth start?
In the 1990s, a doctor in the UK published a study with just 12 children that claimed the MMR (measles, mumps and rubella) vaccine caused autism. Soon after, scientists found the study was poorly done and
based on false information. The journal
retracted (removed) the study, and experts agreed its findings could not be trusted. This doctor has since lost his medical license.
Since then, many large studies around the world have shown that the MMR vaccine
does not cause autism. Still, the study scared many parents and led to fewer children getting vaccinated.
Measles was eliminated in the U.S. in 2000 after millions of children had received the vaccine. After fear spread from the false study, vaccination rates dropped and measles made a comeback. There are now frequent
measles outbreaks in the U.S. again, and our country is about to lose elimination status for the disease
Why is this myth still popular?
Some people think that inflammatory bowel diseased triggered by the MMR vaccine causes autism. This idea comes from the original false paper that started the myth.
Many posts against vaccines on social media present this is a fact, even though it was proved false. Those posts ignore scientists found the paper was wrong, and the
hundreds of studies showing the safety of the MMR vaccine.
Other people think the MMR vaccine causes autism because children get the vaccine around the same time they are screened for and
diagnosed with ASD —between 18 and 30 months of age. They confuse cause and coincidence.
What are the facts behind it?
Just because two things happen at the same time or one after the other, it does not always mean one caused the other. Increasing evidence shows that, even though autism signs show up around the same time children get the MMR vaccine, autism started before they were born.
Researchers studied the possibility of a connection between the MMR vaccine and autism carefully and for many years. They concluded the MMR vaccine does not cause autism. They also found the vaccine against measles doesn't cause inflammatory bowel disease.
Vaccines & thimerosal or mercury
How did the myth start?
Thimerosal is a preservative added to certain vaccines. It stops germs from growing in vaccine containers. It contains a type of mercury, but not the kind that harms your health.
The myth started with confusion between two different types of mercury: methylmercury and ethylmercury. Thimerosal contains ethylmercury, a type of mercury that does not stay in the body. Thimerosal does not have methylmercury, the kind of mercury that stays in the body and makes you sick.
Online content against vaccines has made popular the idea that thimerosal in vaccines causes neurological damage in children.
Why is this myth still popular?
Many people know that
mercury in some fish can be harmful, so when they hear about mercury getting inside the body through vaccines, they think it’s the same substance.
Social media posts against vaccines ignore the difference between the mercury that
can make us sick and the mercury in vaccines, which
can’t harm us.
Social media posts against vaccines often ignore this difference and use frightening images or stories to get an emotional response.
What do you need to know about mercury in vaccines? Pediatrician Joanna Parga-Belinkie shares key facts in this video:
What are the facts behind it?
Mercury is in nature all around us—in the air, soil and water. There are two very different types of mercury: methylmercury and ethylmercury.
Thimerosal contains ethylmercury.
The body quickly processes and eliminates this type of mercury. It does not build up in the body and, as a result, it does not make you sick.
Thimerosal used to be in a lot more vaccines, but since 2001 it’s only in some flu vaccines—less than 4% of them. Cases of pediatricians still using the flu vaccine with thimerosal are rare.
Parents can ask if the flu vaccine their child is going to receive has thimerosal. But keep in mind that most pediatricians use the vaccine without thimerosal already.
Hundreds of studies have proved that thimerosal has never caused neurological problems. Not before, when it was present in a lot more vaccines, and not now, when only one of them has it.
Getting multiple vaccines in a short time
How did the myth start?
Some parents worry that getting several vaccines at one visit is
too much for a child’s body. This idea comes from thinking vaccines work like medicine, where taking too much at once can cause harm.
Why is this myth still popular?
Seeing your baby get several shots in one visit can feel overwhelming. Social media posts against vaccines often use this fear to claim vaccines overload a child’s immune system, even though evidence shows otherwise.
What are the facts behind it?
A child’s immune system is
strong and constantly learning. Every day, it handles thousands of germs from food, air and play. The number of germs in vaccines is very small compared to what children face naturally. Getting more than one vaccine at a time does not weaken the immune system. It helps protect children sooner and with fewer doctor visits.
Vaccines & SIDS
How did the myth start?
Babies receive many of their first vaccines between 2 and 4 months of age. This is also the time when
sudden infant death syndrome (SIDS) is most common. Because the timing overlaps, some people believe vaccines might cause SIDS.
Why is this myth still popular?
When something serious happens after a vaccine, it can be scary and confusing. Social media posts against vaccines often focus on timing alone and ignore scientific evidence.
What are the facts behind it?
SIDS is not fully understood yet, but something we know for sure thanks to scientific studies is that vaccines do not cause SIDS. In fact, vaccinated babies may be at a lower risk of SIDS.
To help prevent SIDS, the American Academy of Pediatrics recommends
safe sleep practices, such as placing babies on their backs and using a firm, clear sleep surface.
Remember
When reviewing facts about vaccines for your child, make sure you
check the source. Have a high level of suspicion if you don't recognize and trust the original source of the content.
And you can always verify information by going to credible sources like HealthyChildren.org, AAP.org and, of course, your child's
pediatrician.
More information
About Dr. Frenck