Immunizations, vaccinations, and shots: What they are and how they can save your life

by Kaiser Permanente |
Bandage on a person's upper arm

Vaccines are a breakthrough of modern medicine. Because of the efforts to vaccinate, smallpox was eradicated from the U.S. in 1949. Other serious diseases like polio are also nearing elimination. The Centers for Disease Control and Prevention (CDC) has even estimated that vaccinations will prevent more than 21 million hospitalizations and 732,000 deaths among children born in the last 20 years.

But vaccination has recently become a hot-button topic. After decades of immunization efforts, some people are now choosing not to get vaccinated. This movement is resulting in an increased number of serious disease cases — like measles, mumps, and pertussis (whooping cough) — that we thought were on their way out.

Incorrect information that associates vaccines with conditions like autism, disabilities, or other medical issues is one of the main reasons people are choosing not to vaccinate. There is no scientific evidence that supports these claims and much of the information that’s shared online is inaccurate.1,2

While the vaccination topic may seem complicated and controversial, it’s important to understand how vaccines work. Unfortunately, there are many myths about vaccines, including what the term means. People often refer to shots, vaccinations, and immunizations as if they’re all the same. But a shot is not necessarily a vaccine — and vaccines were created to result in immunization. Each term is part of a process that builds your body’s defenses against a specific disease or illness.

What is a shot?

A shot, also called an injection, is one method that your doctor or care team could use to inject a helpful substance into your body. Depending on your needs, the shot could contain a medication like insulin or antibiotics — or a vaccine. Examples of vaccination shots include the flu shot or a tetanus shot.

What is a vaccine?

Vaccines are used to help prevent serious diseases or illnesses from happening or spreading. The vaccine itself is a safe substance that contains a small amount of a weakened or dead virus or bacteria. The most common way to get a vaccine is by a shot, but some vaccines can be given to you as a mist you need to inhale or a medication you need to drink. When your body is exposed to a vaccine, your immune system will develop resistance to that disease.

What is immunization?

Immunization is the process of becoming protected — or immune — to a disease or illness. Getting vaccinated is the best way build an immunity against some serious diseases. When your body is exposed to a vaccine, your immune system will produce antibodies against that disease. Your body will then be able to recognize and fight the disease if you’re ever exposed to it. This can significantly lower the impact of a disease or prevent you from catching it.

Immunization via a vaccine also helps prevent the spread of deadly diseases to other people.

Common types of vaccines

Many of the vaccines we get as children protect us from specific illnesses all our lives. Other types of vaccines — like the ones for flu and tetanus — may need to be repeated. Some of the most common vaccines include:

  • Chickenpox
  • Flu (influenza)
  • Haemophilus influenzae type b disease, or Hib disease
  • Hepatitis A
  • Hepatitis B
  • Human papillomavirus (HPV)
  • Measles, mumps, and rubella
  • Meningococcal disease
  • Pneumococcal disease
  • Polio
  • Rotavirus
  • Shingles
  • Tetanus, diphtheria, and pertussis (whooping cough)

Not sure which vaccine you need?

Talk to your doctor if you have any questions about vaccinations. They can view your electronic health record to see which you may need — and answer any questions or concerns you may have. You should also let your doctor know if you have any international coming up. They may recommend certain vaccines depending on your destination.

1 The History of Vaccines: Do Vaccines Cause Autism?, The College of Physicians of Philadelphia, accessed July 2019.

2 Dina Fine Maron, Fact or Fiction?: Vaccines are Dangerous, Scientific American, March 6, 2015.