Skip to main content

Vaccine Safety

Health agencies around the world closely study the safety of vaccines. Hundreds of thousands of people volunteer to be part of clinical trials for vaccines and other drugs.

In the U.S., the Food & Drug Administration (FDA) licenses all vaccines. That means that research scientists and health experts evaluate the safety and effectiveness of vaccines before children and adults receive them.

For example, researchers initially tested 40,000 children to develop the pneumococcal vaccine in the 1970s safely. This vaccine is now routinely given to children at age 2 to protect them against severe bacterial infections like pneumonia and meningitis.

Safe and effective vaccines are part of your child’s routine healthcare

Since the early twentieth century, vaccines have reduced or stamped out many diseases that once killed or disabled large numbers of children. These days, because some of the deadliest childhood diseases have mostly disappeared in the U.S., some parents wonder if vaccinations are even necessary. They may not have first-hand experience with vaccine-preventable diseases like their parents or grandparents had with certain childhood diseases.

For example, large polio outbreaks in the U.S. were common before the polio vaccine was developed in the 1950s. Before we had vaccines, the reality of severe childhood diseases meant that parents expected that:

  • Polio would kill thousands of children and paralyze another 10,000
  • Diphtheria was a common cause of death in school-aged children
  • The mumps virus could infect children’s brains and cause permanent deafness
  • Measles infected three to four million people each year and led to 48,000 hospitalizations
  • Twenty thousand babies were born every year with conditions like blindness and heart disorders due to rubella infections in pregnant women
  • Two hundred thousand children got sick with pertussis (whooping cough), and 9,000 died from the infection

What ingredients go into vaccines?

Vaccine research and development have been conducted in scientific laboratories in the U.S. and worldwide for over 100 years. Millions of children each year receive safe, effective vaccinations that have been approved by the United States Food and Drug Administration or FDA.

Some parents worry that the ingredients in vaccines may not be safe for children. For example, a common misconception is that vaccines can cause autism, a neurological and behavioral disorder. But thanks to years of scientific research, there is no link between vaccines and autism.

Learn more about the what and why of vaccine ingredients below:

Preservatives

Preservatives keep the vaccine from becoming contaminated with microbes like bacteria or fungus.

Where is each ingredient typically found? Eating certain kinds of fish, such as swordfish, contain small amounts of mercury that can pass into the human body.

What is an example? Thimerosal is only used in multi-dose vials of flu vaccine and is not in any vaccines given to children. This type of preservative contains a form of mercury. Most vaccines are single-dose and do not contain thimerosal.

Adjuvants

Adjuvants help boost the body’s immune response to the vaccine.

Where is each ingredient typically found? Aluminum salts are in drinking water, infant formula, antacids, buffered aspirin, and antiperspirants.

What is an example? Aluminum salts.

Stabilizers

Stabilizers protect the active ingredients so that the vaccine remains effective.

Where is each ingredient typically found? Gelatin.

What is an example? Foods like fruit snacks, marshmallows, and gummy bears contain gelatin.

Antibiotics

Antibiotics prevent contamination by bacteria during the vaccine manufacturing process.

Where is each ingredient typically found? Neomycin.

What is an example? Antibiotics that people are most commonly allergic to — like penicillin — are not used in vaccines.

Cell culture ingredients

Laboratory scientists use cultures to grow a virus or bacteria to make the vaccine.

Where is each ingredient typically found? Egg protein.

What is an example? Eggs, or foods containing eggs.

Inactivating ingredients

Inactivating ingredients kill viruses during the manufacturing process.

Where is each ingredient typically found? Formaldehyde.

What is an example? The human body contains a natural form of formaldehyde. The chemical is also in automobile exhaust and household furnishings, such as carpets.

If you have more questions about vaccine ingredients, vaccine safety, or how to get the vaccines your child needs, call Mary Bridge Children’s Immunization Clinic at 253-403-1767.

Common side effects

Like any medication you give your child- even everyday drugstore products like Tylenol — vaccines can cause side effects. Health experts tell parents concerned about possible side effects that vaccinations give your child a lifetime of protection from potentially harmful or deadly diseases. The benefits greatly outweigh the risks.

Severe allergic reactions are very rare. Most commonly, the side effects are mild and only last a day or two. Your child may experience:

  • Soreness, swelling, or redness around the area of the shot
  • Fever
  • Mild rash
  • Muscle aches
  • Tiredness
  • Occasional loss of appetite or vomiting
  • Be sure to contact your primary care provider If you have any medical concerns after your child is vaccinated