Over the years, vaccines have prevented countless cases of disease and saved millions of lives. Vaccination is one of the best ways to protect yourself and your loved one from potentially harmful diseases. Diseases preventable by vaccine can be very serious and may lead to hospitalization or death – especially among infants, young children and the elderly.

Vaccines are made from very small amounts of weak or dead germs that can cause diseases – for example, viruses, bacteria, or toxins. It prepares your body to fight the disease faster and more effectively so you won’t be sick, or at least not weaken the affects of the disease. 

Vaccines are available at doctor’s offices and many pharmacies. Most vaccines are covered by insurance. They don’t just protect you, but also those around you –  like infants and people with weak or failing immune systems – who may not be able to get many vaccines. 

Vaccine Safety

Vaccines are safe and effective. Since they are given to millions of people, including children, they are held to very high safety standards. Every licensed and recommended vaccine goes through years of safety testing. Before a vaccine is ever recommended for use, it’s tested in labs. This process can take several years. 

The Food and Drug Administration (FDA) uses the information from these tests to decide whether to test the vaccine with people. During clinical trials, a vaccine is tested on people who volunteer to get vaccinated. Trials start with 20-100 people, but eventually grow to include thousands of volunteers. These test take several years. Throughout the process, the FDA works closely with the company producing the vaccines to evaluate the vaccine’s safety and effectiveness. All safety concerns must be addressed before the 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, pure, and sterile. The FDA reviews the results of these tests and inspects the factories where the vaccine is made. This helps make sure the vaccines meet standard for both quality and safety. 

Vaccine Types

There are several different types of vaccines. Each designed to teach your immune system how to fight off certain kinds of germs. When scientist create vaccines, they consider:

  • How your immune system responds to the germ
  • Who needs to be vaccinated against the germ
  • The best technology or approach to create the vaccine

Based on these factors, scientists decide which type of vaccine they will make. There are four main types of vaccines.

  • Live-attenuated vaccines
  • Inactivated vaccines
  • Subunit, recombinant, polysaccharide, and conjugate vaccines
  • Toxoid vaccines

Live-attenuated vaccines use weakened forms of the germ that causes the disease. Because these vaccines are so similar to the natural infection, they help prevent it. They create a strong and long-lasting immune response. Just 1 or 2 doses of most live vaccines can give you a lifetime of protection against a germ and the disease it causes. 

Live vaccines are used to protect against: Measles, mumps, rubella, rotavirus, smallpox, chickenpox, and yellow fever.

Inactivated vaccines use the killed version of the germ that causes a disease. They usually don’t provide an immunity that’s strong as live vaccines. You may need several doses over time (booster shots) in order to get ongoing immunity against diseases.

Inactivate vaccines protect against: Hepatitis A, the flu, polio, and rabies. 

Subunit, recombinant, polysaccharide, and conjugate vaccines use specific pieces of the germ – like its protein, sugar, or capsid (casing around the germ). Because they only use a part of the germ, these vaccines give a very strong immune response that targets key parts of the germ. They can also be used on almost everyone who needs them, including people with weakened immune systems and long-term health problems. However, you may need a booster shot to get ongoing protection against diseases. 

These vaccines protect against: Hib disease, Hepatitis B, HPV, Whooping cough, Pneumococcal, Meningococcal, and Shingles.

Toxoid vaccines use a toxin (harmful product) made by the germ that causes diseases. They create immunity to the parts of the germ that cause a disease instead of the germ itself. That means that immune response is targeted to the toxin instead of the whole germ. These may need a booster shot to get ongoing protection against disease. 

Toxoid vaccines are used to protect against diphtheria and tetanus. 


Links to various resources on the topics discuss on this page. 

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