What are the different types of vaccines?

What kinds of vaccines are there?

There are several kinds of vaccines currently on the market, and the type of vaccine you receive depends on the disease and on your health status. In this video, we’ll talk about three different common types of vaccines, as well as new vaccines currently in development. Each of the different types of vaccines helps to teach your body to recognize and respond to invading pathogens to prevent you from getting sick.

Live, attenuated vaccines

Live, attenuated vaccines are they closest to a natural infection. They contain a weakened version of a living virus or bacteria. These types of vaccines teach your immune system what the infection might look like without causing a severe illness. But because these vaccines contain living pathogens, they can’t be given to people with weak immune systems. The MMR and chickenpox vaccines are examples of live, attenuated vaccines.

Inactivated vaccines

Inactivated vaccines contain an inactivated or dead version of a virus or pathogen. They are not as similar to a real infection as live, attenuated vaccines so often people need multiple doses of this kind of vaccine to maintain immunity. These are safer for people who are immunocompromised. The injectable flu vaccine is an inactivated vaccine, as is the polio vaccine currently distributed in the United States.

Subunit vaccines contain only parts of a virus or bacteria instead of a whole pathogen. This lets your immune system directly target the important antigen of the pathogen and tends to have fewer side effects than inactivated or live attenuated vaccines. The whooping cough, or pertussis, component of the TDaP vaccine is a subunit vaccine.

Other, newer kinds of vaccines

There are other kinds of vaccines, too, that are specialized to deal with unique types of bacteria and bacterial toxins, like conjugate and toxoid vaccines. For example, the TDaP vaccine contains diphtheria and tetanus toxoids.

Some new kinds of vaccines are being developed, including mRNA and vector-based vaccines. These use your cell’s own machinery to produce antigens for certain pathogens. As of October 2020, the National Institute of Allergies and Infectious Disease and the pharmaceutical companies Moderna and Pfizer are currently conducting the first large-scale, phase 3 clinical trial of an mRNA vaccine against SARS-CoV-2, the virus that causes COVID-19. These new types of vaccines may lead to safer and easier-to-produce vaccines against diseases in the future.

No matter what type of vaccine is used, they all have the same goal: teaching your immune system to recognize and respond to bacteria and viruses so it can fight off potential infections in the future.

Watch part one: How do vaccines work?

Watch part three: How are vaccines made?

Watch part four: How does the FDA approve vaccines?