How do vaccinations work?


Vaccinations work by helping the body create antibodies to fight disease.

When germs invade the body, they cause an infection. Once the body fights off the infection, the body is left with a supply of cells called antibodies that help recognize and fight that disease in the future. Vaccinations introduce a weakened form of the disease into the body. The body then makes antibodies to fight the invaders, so if the disease ever attacks, the antibodies will destroy these invaders, providing protection against the disease.

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Dr. Kelly Traver

A vaccination works by giving you a very small dose of a bacterium, virus, or toxin to prepare your immune system to quickly mobilize and fight in the event you are exposed to it in the future.

Vaccinations work by stimulating the body's immune system before you're exposed to an invader such as a virus or bacteria, so that you're already protected when you encounter it. All vaccines are designed to affect the immune system in some way.

Prophylactic vaccines are designed to stimulate a response of the immune system to a modified version of the invader so that when you are infected with the actual virus or bacteria, it can quickly mount a major offense against the invader before you become sick.

Therapeutic vaccines are designed to strengthen the immune system's response to cancer or other abnormal cells.

Vaccinations work by injecting a tiny amount of a weakened or killed germ into the body so the immune system learns to recognize that germ. This way, if the germ ever attacks, the immune system can fight it off very quickly to prevent infection so people don’t get sick.

Immunizations expose children to a minuscule, highly safe amount of a virus or bacteria that has been killed, is very weak or has been artificially created. The immune system quickly learns to recognize this invader and defend the body against future attacks. Consequently, the next time the body is exposed to the virus or bacteria, the immune system kicks in and either prevents infection or weakens the severity of the illness.

Continue Learning about Vaccines & Immunizations

Vaccines & Immunizations

Vaccines & Immunizations

Vaccines are commonly given to children in the form of a shot to help prevent serious diseases like measles and mumps. Vaccines are developed using either dead strains of a disease, weakened strains, or strains of a different dise...

ase. As adults, we receive flu vaccines or may need a booster of childhood vaccines to retain immunity. Travelers may receive vaccines either as a condition of entry to a country, or on recommendation of health officials. Generally there is little or no reaction to a vaccine, but in some cases the vaccine may cause an allergic reaction or a temporary, mild illness. Some vaccines are not safe for pregnant women, so it’s important to check with a healthcare professional.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.