Cincinnati Children's provides answers to frequently asked questions about childhood vaccinations.

Are Vaccines Important?

Yes! Vaccination is the single most important thing you can do to protect your child’s health – not just today, but for many years to come.  Just because a disease is not common doesn’t mean that it doesn’t exist. 

The disease is still a threat, and often the only thing preventing the disease from surfacing is the vaccine.  Outbreaks of vaccine-preventable disease have occurred both here and in other countries where children have not been immunized.

Are Vaccines Dangerous?

The most common risks of vaccines include mild side effects such as pain and redness at the site of injection as well as low-grade fevers.

The vast majority of side effects are not severe and resolve within one to two days.

Who Determines the Childhood Vaccination Schedule Most Commonly Followed by Pediatricians?

Vaccine schedules in the U.S. are developed by the Advisory Committee on Immunization Practices of the national Centers for Disease Control and Prevention.

This group of vaccine experts receives input from the American Academy of Pediatrics and the American Academy of Family Physicians. This schedule is published yearly in January.

There Has Been a Lot of Talk Linking Vaccines to Autism, Particularly the Measles Mumps-Rubella Vaccine. Does the MMR Vaccine Cause Autism?

No. More than a dozen studies have been published showing that autism is not associated with receiving vaccines. We have more than sufficient information to say that vaccines, including MMR, do not cause autism.

Autism, now more commonly referred to as autism spectrum disorder (ASD), is a collection of several disorders that have common areas of abnormality. The main areas are social skills, communication skills, and repetitive or obsessive traits. These abnormalities are typically noted between the first and second year of life. The MMR is also typically administered at this time.

The incorrect notion that the two might be linked was boosted by a study published by a British physician who said the MMR, and specifically the measles vaccine, caused autism. This study has been discredited, and the co-authors of the study subsequently published a formal retraction.

While we still do not know exactly what causes autism, it is likely the result of many factors, including genetics, abnormal brain growth, environmental triggers and prematurity. Further studies to evaluate a link between vaccines and ASD are not beneficial and expend precious resources that could be redirected toward research critical to understanding and hopefully preventing autism spectrum disorder.

How Important Is It for a Child, Particularly an Infant, to Receive a Thimerosal-Free Flu Shot?

Thimerosal, composed of ethyl mercury, is a compound that can be used as a preservative in vaccines. Ethyl mercury is quickly eliminated by the body and DOES NOT cause mercury poisoning.

Mercury poisoning is caused by methyl mercury, a compound that does build up in the body and can result in damage to the nervous system and brain.

So, while the two types of mercury sound similar, they are very different.

Thimerosal has not been shown to be toxic. But thimerosal has been removed from vaccines whenever possible.

Currently, the only childhood vaccine that contains thimerosal is found in multi-dose vials of flu vaccine.

However, more than an adequate number of thimerosal-free single dose containers of flu vaccine are produced for children each year.

As of 2019, approximately 85% of the flu vaccine produced was thimerosal-free. Also, even when it was present in vaccines, the total amount of thimerosal containing mercury received by an infant was less than half the amount of mercury a baby receives from its mother if breast fed for six months. When looking only at flu shots, breastfed babies receive 25 times more mercury in the breast milk than they would from a flu shot.

If Kids Don’t Get That Sick from COVID-19, Do They Need to Get Vaccinated? 

Currently, there is no vaccine against COVID-19 authorized for children 15 or younger. However, when a COVID vaccine is authorized for children, Cincinnati Children’s will advocate that every eligible child be vaccinated against COVID.

As of Dec. 31, 2020, more than 2.2 million kids in the United States had been infected with COVID-19 – and thousands of them had been hospitalized. At least 180 previously healthy kids died of COVID. 

The vaccine is important for the health and safety of children, but also to prevent them from spreading the disease to adults such as parents, grandparents, and teachers. Vaccines are going to be critical to get rid of the pandemic.  It’s much safer to get the vaccine than to contract the disease. 

Should Kids Get Flu Shots and the COVID-19 Vaccine?

We strongly advocate that every child over 6 months old get a yearly flu shot. Once the COVID-19 vaccine is authorized for children, Cincinnati Children’s will also advocate that every eligible child be vaccinated against COVID.

Do Vaccines Contain Aluminum? Are the Amounts Harmful?

Many vaccines contain alum, which has been used in vaccines for over 75 years and has been found to be safe. Alum is an adjuvant. Adjuvants are used to help our bodies create a better immune response to vaccines, making the vaccines more effective. Without an adjuvant, children may need more shots or have lower immunity to the infections.

We routinely ingest aluminum. For example, a quart of infant formula contains about the same amount of aluminum as the entire schedule of recommended pediatric vaccines.

Do Vaccines Contain Fetal Tissue?

No. Some vaccines against viruses (chickenpox, rubella and hepatitis A) use fetal cells to grow the vaccine viruses. But once the vaccine virus is grown, it is purified so that no human cells or human genetic material (DNA) is in the vaccine.

Do Vaccines Contain Gelatin From Pigs?

Some viral vaccines contain gelatin to stabilize vaccines so that they remain effective after manufacture. All gelatin contained in vaccines is porcine in origin.

However, leaders of both the Jewish and Muslim faiths have declared that pork-derived additives in medicines are permitted.

Rabbi Abraham Adler of the Kashrus and Medicines Information Service in the United Kingdom has advised that “according to Jewish laws, there is no problem with porcine or other animal-derived ingredients in non-oral products. This includes vaccines, injections, suppositories, creams and ointments.”

Scholars of the Islamic Organization for Medical Sciences have also determined that the process through which pork is transformed into gelatin alters it enough to make vaccination permissible for Muslims.

Some Parents Consider Not Getting Their Children Vaccinated. What Are the Risks of Not Vaccinating?

Cases of measles, mumps and whooping cough have increased in the U.S., occurring overwhelmingly in unimmunized children. In most outbreaks of measles, it has been found that unimmunized children were 20 times more likely to contract measles than vaccinated children.

So, parents choosing not to immunize their children are putting them at risk of getting infections that are far more serious than the risks associated with vaccines.

Some Parents Consider Delaying Their Child’s Vaccinations or Delaying Certain Vaccinations. What Are the Risks?

There is no known benefit from delaying vaccination – and no increased risk of receiving multiple vaccines at one time.

Delaying vaccines leaves a child susceptible to the disease for a longer period of time, often at the age the child is most at risk from that disease.

Also, it has been proven that children who use an alternative vaccine schedule are significantly more likely to never complete the recommended vaccine schedule.

Isn’t the United States Safe from Diseases Such as Polio? Why Vaccinate a Child for That?

Airplane travel – and our ability to cross the globe in under a day – means anyone could be exposed to any infection before the contagious person even begins to show symptoms. Immunizations are needed to keep our children safe.

To date, throughout the world, smallpox is the only infectious disease that has been eradicated. Vaccines can safeguard our children against many others.

Why Would My Daughter or Son Need an HPV Vaccine?

HPV is a vaccine to prevent cancer.

Girls vaccinated against HPV have a 90% decreased risk of developing cervical cancer as compared to unvaccinated girls.

We now know that the HPV vaccine can prevent almost 70% of throat cancers.

The vaccine also can almost entirely eliminate the risk of genital warts. While not deadly, genital warts cause great emotional distress and are very difficult and painful to treat.

The recommended schedule is for both girls and boys to be vaccinated against HPV starting at age 11 or 12, but vaccine as young as 9 is allowable.

Is Cincinnati Children’s One of the World’s Top Vaccine Research Centers?

Yes. In 1927, businessman James N. Gamble of Cincinnati-based Procter & Gamble Co. made a transformational donation to launch what is now called the Gamble Center for Vaccine Research.

It includes a Vaccine and Treatment Evaluation Unit funded by the National Institutes of Health. Currently, Cincinnati Children’s is a leader in clinical trials for the Pfizer COVID-19 vaccine in kids ages 12-15 as well as ages 16-17 and adults. The medical center is also conducting a clinical trial of the AstraZeneca COVID-19 vaccine candidate in adults.



Reviewed January 2021 by Robert Frenck, MD, director of Gamble Vaccine Research Center at Cincinnati Children’s; and Mary Carol Burkhardt, MD, Cincinnati Children’s associate division director, Primary Care, Division of General and Community Pediatrics, and medical director of Hopple Street Health Center.