Vaccines are safe and effective. Because vaccines are given to millions of healthy people — including children — to prevent serious diseases, they’re held to very high safety standards.
In this article, you’ll learn more about vaccine safety — and get answers to common questions about vaccine side effects.
How are vaccines tested for safety?
Every licensed and recommended vaccine goes through years of safety testing including:
• Testing and evaluation of the vaccine before it’s licensed by the Food and Drug Administration (FDA) and recommended for use by the Centers for Disease Control and Prevention (CDC)
• Monitoring the vaccine’s safety after it is recommended for infants, children, or adults
Vaccines are tested before they’re recommended for use.
Before a vaccine is ever recommended for use, it’s tested in labs. This process can take several years. FDA uses the information from these tests to decide whether to test the vaccine with people.
During a clinical trial, a vaccine is tested on people who volunteer to get vaccinated. Clinical trials start with 20 to 100 volunteers, but eventually include thousands of volunteers. These tests take several years and answer important questions like:
• Is the vaccine safe?
• What dose (amount) works best?
• How does the immune system react to it?
Throughout the process, FDA works closely with the company producing the vaccine to evaluate the vaccine’s safety and effectiveness. All safety concerns must be addressed before FDA licenses a vaccine.
Every batch of vaccines is tested for quality and safety.
Once a vaccine is approved, it continues to be tested. The company that makes the vaccine tests batches to make sure the vaccine is:
• Potent (It works like it’s supposed to)
• Pure (Certain ingredients used during production have been removed)
• Sterile (It doesn’t have any outside germs)
FDA reviews the results of these tests and inspects the factories where the vaccine is made. This helps make sure the vaccines meet standards for both quality and safety.
Vaccines are monitored after they’re recommended to the public.
Once a vaccine is licensed and recommended for use, FDA, CDC, and other federal agencies continue to monitor its safety. Any medicine can cause reactions, but serious vaccine side effects are very rare. It’s natural to want to understand the potential risks of vaccination, especially when the benefits are invisible. You’ll never know how many times your child is exposed to a vaccine-preventable disease and makes use of his or her vaccine-induced immunity. Fortunately, we have sufficient data to help parents like you weigh the pros and cons. Here’s what you need to know.
Vaccination saves lives.
The primary benefit of vaccination is that it prevents disease. Immunization is considered one of the greatest public health achievements of the 20th century, and experts agree that immunization is key to staying healthy. In one year, vaccines prevent more than 8,500 child hospitalizations in Colorado, 33,000 deaths in the U.S., and between 2 and 3 million deaths worldwide.
These drops in disease rates are primarily thanks to vaccination, not sanitation or improved hygiene. (If that were the case, all diseases would start declining around the same time.) While the diseases we vaccinate against have declined, they haven’t disappeared. While vaccines have become increasingly accessible in the U.S., other countries are not so lucky. As we have seen in the U.S. and in other countries, if we stop vaccinating, vaccine preventable diseases can and will return. This is why we still vaccinate against diseases we no longer see in the U.S. All it takes is one infected traveler from another country where a disease hasn’t been eliminated to spark an outbreak.
Vaccination protects the people you care about.
Vaccination is not just a personal choice. The vaccinated community helps to protect those who are not vaccinated, a concept known as “herd immunity” or “community immunity.” Simply put, when a person is vaccinated, they prevent disease from being spread to others in the community, including:
• Babies too young to receive vaccines
• Unvaccinated children and adults
• Pregnant women
• The elderly
• Individuals with weakened immune systems, such as those with asthma, chronic illness, or undergoing treatment for cancer
• Individuals who are allergic to vaccine components
When less than 90% of children are immunized in a particular community, these pockets of low vaccination create an environment where infectious diseases can take hold and spread. Only a very small percentage of children in the U.S. are completely unvaccinated—about 3%—however, they tend to cluster in certain geographic areas. Clustering of unvaccinated individuals in certain communities diminishes the benefits of herd immunity for everyone living in that area.
Vaccines are cost effective.
Not only do vaccines save lives, they save money too. It is always cheaper to prevent a disease than to treat it. The routine childhood immunization program in one birth cohort saves $13.6 billion in direct costs. Every dollar spent on childhood immunizations saves $18.40. In Colorado, the cost of treating 538 children hospitalized for vaccine-preventable diseases in one year totaled $29.2 million.
Vaccines are safe.
Vaccines undergo rigorous safety testing prior to being approved by the Food and Drug Administration (FDA) and are continually monitored for safety. Vaccines are also studied to be administered together to protect children.
The risks of natural infection outweigh the risks of immunization for every recommended vaccine.
Parents who choose not to vaccinate often do so to avoid risk, but choosing not to vaccinate is the riskier choice. So choose wisely.