How Vaccines Work—Catherine Rasgaitis

To achieve herd immunity without vaccines, people would have to rely on gaining immunity through prior infections. In other words, the disease would be allowed to spread unrestricted through a community until enough people caught the disease and developed long-lasting immunity on their own. However, letting a virus run rampant through a community is both dangerous and unethical. Allowing any disease to run its course without taking safety measures would undoubtedly lead to unwarranted human suffering and death.

How does a vaccine help? Vaccines effectively train a person’s immune system to fight diseases through proteins called antibodies. Antibodies are vital to immunity because they help identify and trigger immune responses to foreign invaders in the body. Antibodies also stay in the immune system even after an infection has been eradicated. This means that if the antibodies come in contact with the same condition again, the person’s immune system will know how to fight it off properly.

To stimulate the body’s immune system, most vaccines will also have an antigen, a small part of the infection-causing organism or the whole organism in a weakened form. Antigens represent the foreign viruses or substances that the antibodies must identify to signal the immune system to respond accordingly.

However, some modern vaccines are changing the need for the antigen. Rather than introducing the foreign infection itself into the immune system, some vaccines use a blueprint of the antigen’s traits. Regardless of using a “true antigen” or a blueprint of its traits in a vaccine, any weakened versions of the antigen are not designed to give the disease to a patient. The goal is to trigger the immune system’s response to fight off the virus.

When a person’s immune system recognizes a virus it has defeated before, the immune system can respond even faster and more effectively than in its first encounter. This is what gives vaccines their value. By training your immune system how to respond to the disease before you have the chance to come in contact with it on your own, your body will be more prepared to recognize and overcome the disease more efficiently. In some cases, when your immune system reacts immediately to a disease that it recognizes, your body can overcome a virus before you even experience the symptoms! At the very least, getting vaccinated can help ease symptoms and prevent an infection from worsening.

With vaccines being developed and distributed across the world during the ongoing COVID-19 crisis, it is crucial that people understand the importance of vaccines and how they keep us safe. Spreading awareness and education about vaccines can help make your community a safer, healthier place!


“Coronavirus Disease (COVID-19): Herd Immunity, Lockdowns and COVID-19.” World Health Organization, World Health Organization, 31 Dec. 2020,

“How Are Vaccines Developed?” World Health Organization, World Health Organization, 8 Dec. 2020,

“How Vaccines Work.” Celebrate Vaccines, British Society for Immunology,

“Immunization Basics.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 16 May 2018,

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