Understanding How Vaccines Work
Vaccines greatly reduce the risk of infection by working with the body’s natural defenses to safely develop immunity to disease.
The immune system is the body's defense against infection. To understand how vaccines work, it is helpful to first look at how the body fights illness. When germs, such as bacteria or viruses, invade the body, they attack and multiply. This invasion is called an infection, and the infection is what causes illness. The immune system uses several tools to fight infection. Vaccines help develop immunity by imitating an infection. This type of infection, however, does not cause illness, but it does cause the immune system to produce T-lymphocytes and antibodies.
Today there are four main types of vaccines that infants and young children commonly receive:
Live vaccines use a weakened (or attenuated) form of the germ that causes a disease.
Inactivated vaccines use the killed version of the germ that causes a disease.
Toxoid vaccines use a toxin (harmful product) made by the germ that causes a disease.
Subunit, Conjugate & other vaccines use specific pieces of the germ - like its protein, sugar, or capsid (a casing around the germ).
Vaccines, like any medication, can cause side effects. The most common side effects are mild. However, many vaccine-preventable disease symptoms can be serious, or even fatal. Although many of these diseases are rare in this country, they do circulate around the world and can be brought into the United States, putting unvaccinated children at risk. Even with advances in health care, the diseases that vaccines prevent can still be very serious and getting a vaccination could be the best way to prevent them.
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