Even though vaccines protect your child from a long list of dangerous diseases and come fully recommended by your child’s pediatrician, it's understandable to wonder about the possible risks.
But vaccines exist to protect children and communities. In fact, if it weren’t for vaccinations, many diseases — like chickenpox, polio, diphtheria, rubella, and mumps — would circulate more than they do today. Other immunizations — such the COVID-19 vaccine and flu shot — help ward off commonly transmitted viruses.[1]
Still, it’s normal to have concerns, especially these days, when you’re likely to come across unsettling stories online or even have a family member or friend try to convince you that immunizations are risky or dangerous.
The good news is that these concerns are completely unfounded. What’s more, you shouldn’t let them stop you from sticking with the recommended vaccine schedule.
Here’s what every parent should know about how vaccines keep children safe, plus the myths that you should never believe.
How do vaccines protect children?
Vaccines safeguard your child’s health by protecting her against harmful, potentially life-threatening diseases. While no vaccine is foolproof, the risk that your child will contract a disease after being immunized is greatly lowered.
But vaccines don’t just go a long way towards keeping your child healthy. Immunizing your little one also keeps other kids from getting sick, and vice versa, through something called herd immunity. This also helps protect people who can’t get vaccinated, such as newborns or those with weakened immune systems. And if everyone were vaccinated, outbreaks could be prevented altogether.
Vaccines also ensure a safer future for everyone. Over time, widespread immunization can make a disease so rare that it officially becomes medical history. When you take your child for her shots, you're doing your small part to protect the health of your grandchildren, great grandchildren, and beyond.
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Here are some common vaccine myths you may have heard, and why you shouldn't believe them.
"Giving multiple vaccines at once — either during the same visit or in a combo shot — isn’t safe."
Truth: Combo immunizations mean fewer shots for kids overall and make it easier to stay on schedule.
More vaccines are being given as combination shots these days, like the one that combines DTaP, polio, and hepatitis B in a single shot. Combo shots offer the same protection as individual shots just with fewer trips to the doctor, and they’ve gone through the same rigorous testing and approval process to ensure that they're safe.[2]
And of course, there are systems in place to watch for any serious reactions that might occur.
Speaking of reactions, the side effects are usually mild. Combo vaccines might cause a little more pain or swelling at the injection site, but they're well worth it since your child will have to sit through fewer shots overall.
"Herd immunity means that my child can’t get sick."
Truth: Think you don’t have to vaccinate your child as long as everyone else gets their shots? You're risking your little one’s health — and the health of others.
It’s true that herd immunity helps provide protection against many less common diseases. But this protection is far from guaranteed: Many of the diseases we vaccinate against are still common in other parts of the world, so your child could become infected by just one traveler.
What’s more, if your child as well as others aren’t getting immunized, it sets the stage for a potential outbreak. And she could infect others too — even those who are immunized, since immunization doesn’t offer 100% protection against a disease. (The 2025 measles outbreak that’s ongoing in parts of the U.S., for instance, has occurred because a high enough percentage of families had opted out of the MMR vaccine.)[3]
The numbers speak for themselves: If 80% of a population has been immunized against a virus, 4 out of 5 people who are exposed to a disease probably won’t get sick. But one still will. But if everyone in a population has been immunized, the chances of someone even being exposed in the first place become extremely low.
Finally? Keep in mind that herd immunity doesn’t work for diseases like tetanus, which aren’t transmitted from person to person. An unvaccinated child could get tetanus from stepping on a rusty nail, for instance.
"Vaccines have already wiped out childhood diseases."
Truth: Many of those diseases are still out there. Vaccines have just made them much rarer.
If your child isn't immunized, she's at increased risk of getting sick. Multiple mumps and whooping cough outbreaks have occurred in the U.S. in recent years.
There's also the fact that diseases that are rare in the U.S. are still widespread in other countries where vaccines aren’t prevalent. Which means they're only a plane ride away, and can still pose a risk to unvaccinated kids.
Finally, many vaccine-preventable diseases pose the most danger when children are very young. So if an outbreak does occur and your child isn’t immunized, she's at higher risk of serious complications and even death.
"One vaccine in a series gives a child enough protection."
Truth: Top disease experts have studied exactly how many doses are needed in order to provide the most protection.
For some vaccines, it takes more than one shot to build up enough immunity to protect against a disease, as well as boost immunity that can fade and provide immunity from germs that change over time, like the flu or COVID-19.
If a vaccine calls for multiple rounds of a shot, a child who gets just one round won't receive full immunity — and is still at a higher risk of contracting the disease.
That’s why it's so important to make sure your child gets all of the doses in a vaccine series at the recommended intervals. Skipping out on even one could leave her unprotected and put her at risk of getting seriously sick.[4]
"Multiple vaccines for young children put them at increased risk of other diseases."
Truth: There's no evidence that giving children multiple vaccines at once makes them more likely to get any illness.
It’s safe for your little one to receive multiple shots at the same well-child visit. There's no connection between the administration of multiple vaccines and an increased likelihood of getting allergies, diabetes, infectious disease, or any other illness.[5]
Remember, vaccines are given to young children precisely because they’re at risk of getting seriously ill or dying from a disease, which is why your baby may receive multiple vaccines at once during some doctor’s visits. Receiving multiple shots doesn’t increase your child’s chances of getting sick — it greatly lowers them.
"Shots are very painful for a baby."
Truth: The brief pinch she feels is far less painful than what she (and you) would go through if she got sick.
There’s no denying that seeing your baby cry from a shot can be hard. But there are things you can do to make the shot easier on your little one.
Babies who are being held during a vaccine and who are breastfed or given a bottle immediately before or after experience less pain, studies show. And don't discount simple distraction: Sometimes a toy, book, or comfort object like a pacifier or favorite lovey can take your baby’s focus off the shot too.
Comforting your child post-vaccine and offering a reward for toddlers and preschoolers, such as a trip to the ice cream shop or toy store for a special treat, can also help make the experience easier. You can also ask your pediatrician about other options to ease your baby's discomfort.
Lastly, the desire to minimize painful shots for your baby makes another case for the benefit of combination vaccines. Getting immunized for multiple diseases in one go means fewer needles — and ouchies — overall.
Want more info about fact vs. fiction when it comes to vaccines? Find it on the What to Expect app.
"Parents should be concerned about mercury in vaccines."
Truth: The concern about mercury stems from thimerosal, and all routine vaccines are thimerosal-free except for some flu shots.
Thimerosal, a mercury-containing compound, prevents the growth of harmful bacteria and fungus. It was once used as a preservative in some vaccines to protect against contamination.
But most childhood vaccines, including MMR, polio, varicella, and PCV, never contained thimerosal to begin with. And since 2001, all routine vaccines are thimerosal-free with the exception of some flu vaccines that come from multi-dose vials.[6]
Keep in mind that the decision to remove thimerosal from vaccines wasn’t prompted by studies showing that the compound is dangerous to kids. Instead, it was made as a precaution to reduce infants' exposure to mercury overall.
For thimerosal still used in flu vaccines, the amount is extremely small, and research has repeatedly proven that it’s not harmful. (In fact, the amount of mercury in your child’s flu vaccine leaves her body faster than the mercury found in fish.)
If thimerosal in your child’s flu vaccine still makes you uncomfortable, don't let it stop you from getting her seasonal shot. Thimerosal-free flu vaccines are available, so ask the pediatrician if that's an option for your baby. (It’s recommended that all children get the flu shot every season starting at 6 months old.)
"Vaccines cause autism or other developmental delays."
Truth: Despite the continued spread of misinformation, childhood vaccines do not cause autism spectrum disorders (ASD).
This finding has been shown in multiple large-scale studies, which have been compiled by the American Academy of Pediatrics (AAP) for parents to read the evidence for themselves. None of this research has found any association between vaccines and autism.[7]
If you’re wondering how the vaccine-autism scare came about to begin with, it all started in 1998 when a small study published in The Lancet suggested a possible link between the MMR shot and autism. In 2010, The Lancet retracted the study. The doctor who conducted the study had his medical license revoked for fudging the data, manipulating the study outcomes, and misreporting the results.
"The person who did that study was found to have falsified [it]," says Gina Posner, M.D., a board-certified pediatrician at MemorialCare Medical Group in Fountain Valley, California, and a member of the What to Expect Medical Review Board. "He went on to lose his medical license."
The highly flawed study was declared an "elaborate fraud" by the British Medical Journal in 2011. And in 2019, a decade-long study looking at over 650,000 children found no link between autism and the MMR vaccine.
In other words, there's no credibility to the myth that vaccines cause autism.
"Preemie babies are too fragile to get vaccinated."
Truth: Regardless of your preemie's "birth age" or weight, it’s perfectly safe for her to get vaccinated.
Not only are vaccines safe for preemies, they’re incredibly important. Compared to their full-term counterparts, premature babies are even more vulnerable to the diseases that vaccines protect against. And if they do get sick, they’re at higher risk of complications.
If your little one was born early, there's no need to adjust the vaccine schedule to her "birth age" or wait until she gets bigger, and she’s not at increased risk of any side effects.[8]
The one sometimes-exception is the hepatitis B vaccine. Preemies weighing at least 4 pounds, 6 ounces should get their first HepB shot shortly after birth, just like full-term infants. But for babies weighing less than that, the AAP recommends waiting until the baby reaches 1 month of age or is discharged from the hospital, whichever comes first.
Your pediatrician will determine when your baby should get her first HepB shot and when the subsequent ones will be administered.
"Vaccines often cause allergic reactions."
Truth: Vaccines do have the potential to cause reactions, but it's extremely rare.
Vaccine-related allergic reactions occur in around 1 out of a million people. Given how dangerous the diseases are that vaccines protect against, this possible but very small risk isn’t a good reason to skip out on shots.
If your child does have an allergic reaction to an immunization, it would likely happen within 30 minutes of the shot being administered, and her doctor could treat it with steroids or epinephrine. If that happened, your doctor would likely recommend against giving your child additional doses of the vaccine.
Of course, if your baby has a known allergy to any common vaccine ingredients — like yeast, eggs, latex, gelatin, or neomycin — you should let the doctor or nurse know before it’s time for your little one to get her shot.
Depending on the severity of the allergy, your baby's pediatrician might opt to not give a certain vaccine. But that's not always the case. For instance, children with egg allergies are often still able to safely receive a seasonal flu shot.
Ultimately, the risk of having an allergic reaction to a vaccine is very, very low. If your child has a known allergy to something in an upcoming vaccine, bring it up with her doctor, but don’t automatically assume all shots are off the table. In some cases, your baby may still be able to receive certain immunizations safely.
"The aluminum found in some vaccines is dangerous for my baby."
Truth: There is a very small amount of aluminum in some vaccines to boost their effectiveness, and it's completely safe.
It’s true that some vaccines contain small amounts of aluminum. It’s used as an “adjuvant,” meaning aluminum is added to make the shots more effective so that smaller doses of the active ingredient are needed. Aluminum has been used in immunizations for more than 70 years, and rigorous research has repeatedly found that the levels in vaccines are safe.[9]
In fact, the amount of aluminum your child is exposed to through vaccines is pretty small compared to the exposure she gets pretty much everywhere else: There's more aluminum in breast milk, formula, and other foods than there is in vaccines.
"Kids get more vaccines than they used to, which could be dangerous."
Truth: Kids get more shots because we can now protect against more diseases — and the amount they receive has been found to be very safe.
It’s true that kids today get more vaccines than they did in the '80s or '90s, but that’s because there are now newer vaccines available to protect against more diseases. Vaccines for hepatitis A and B, varicella (chickenpox), rotavirus, and pneumococcal disease weren’t available for children who were born in the ‘50s and ‘60s, for example. Children today may also get more shots because some vaccinations require multiple doses to provide full immunity.
But just as it’s safe to receive multiple shots at once, research has found that the amount of shots kids receive today is also very safe. All of these vaccines can’t “overwhelm” the immune system (in fact, our immune systems are exposed to more than that in our daily lives).
- Vaccines exist to protect children and communities. Without vaccines, many once-common diseases such as smallpox, polio, and diphtheria that can be very dangerous (and even deadly) for kids would circulate much more than they do today.
- Still, it’s normal to have concerns, especially these days, when you’re likely to come across unsettling stories online or even have a family member or friend try to convince you that immunizations are risky or dangerous.
- The good news is that any myths you may have heard about vaccines being unsafe are false. Many, many rigorous studies and top disease experts have found that the immunizations your child receives are very safe, are likely to cause only mild side effects (if any at all), and are extremely effective at protecting your little one from dangerous diseases.
- If you have any concerns, voice them to your child's pediatrician, who can help put your mind at ease.
"My child shouldn’t get vaccinated if she has a cold."
Truth: Symptoms like a runny nose, cough, or low fever aren’t usually reasons to put off a shot. Neither is taking antibiotics.
Vaccines won't make a mild illness worse, and they won't keep the vaccine from being effective. (And considering how often little ones get sick, rescheduling a vaccine because of a mild cold could very well throw off your child’s vaccine schedule.)
If your baby is dealing with something more serious, like a high fever, it might be worth holding off on the shot until she's feeling better. Since her immune system is already battling an illness, getting a vaccine on top of that could affect how her body responds to the shot.
In either case, it's worth giving her pediatrician a call before bringing your baby in for her vaccine. Based on your sweetie's symptoms, the doctor can determine whether delaying the shot makes sense. And you can set up another appointment right then and there, so it doesn't fall through the cracks.
The bottom line? Vaccines protect children and communities from serious and even life-threatening illnesses. And they work best when everyone receives them, in the recommended number of doses and on the recommended timetable.
“We get our kids fully vaccinated on schedule,” says What to Expect Community parent adstru75. “A little fever is nothing compared to polio, measles, etc. My grandfather had polio and I would never think about leaving my child exposed to something that could be prevented. Plus, herd immunity is real and important.”
Of course, it’s normal to have questions about your child’s shots. But don’t let those stop you from having her vaccinated. Instead, voice any concerns you have with her pediatrician, who will be able to share the facts — and hopefully, put your mind at ease.
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