Skip to Content

SHARE

Immunity

Immunity is a person's resistance to (or protection from) a disease. A person may be born with temporary protection from certain diseases, or a person may be protected after having an infection or immunization (vaccination).

Immunity occurs because the body's immune system recognizes a foreign substance (such as a virus or bacteria) as potentially harmful and sends antibodies (proteins made by the immune system) to destroy it.

Immunity may be temporary or permanent, depending on the nature of the disease, how the person became immune, and other factors. For instance, some vaccines give a person lifelong immunity against a disease and only have to be given one time. Others have to be given on a regular schedule (every 10 years, for example) because they do not provide permanent immunity. Partial immunity implies some degree of protection from a disease.

Decision Points

Our interactive Decision Points guide you through making key health decisions by combining medical information with your personal information.

You'll find Decision Points to help you answer questions about:

Interactive Tools

Get started learning more about your health!

Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups, and pregnancy.

Symptom Checker

Feeling under the weather?

Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.