Vaccine: Inactivated, killed, or weakened disease-causing organisms (for example, mumps or measles virus) that are injected into the body for the purpose of developing resistance to the disease. The body’s immune system responds to the vaccine by forming antibodies and activating certain immune system cells that are specifically targeted to those particular organisms. The result is that the body is then resistant (immune) to the disease for a specific period of time; in some cases, the immunity lasts forever. Development of a cancer vaccine is a subject of intense research. (See immune system and antibody).

Vaginitis: Any inflammation (swelling) of the vagina. Atrophic vaginitis is an inflammation of the vagina in which the vaginal tissue becomes thin and dry. This condition may occur after menopause due to a lack of estrogen. (See also menopause.) An estrogen cream may be prescribed to relieve this problem. Vaginitis can also be a side effect of chemotherapy.