A vaccine is a biological preparation that contains weakened or inactive parts of a particular virus or bacterium. It can also include a blueprint for making the target disease's antigens. Vaccines work by stimulating the immune system to recognize these antigens as threats, helping the body to develop a defense against future infections. This process is known as active acquired immunity.
Vaccine
Definition:A vaccine is a substance that helps the body build immunity against specific diseases.
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Vaccines train your immune system to recognize and fight specific infections before they cause serious illness. This guide explains how vaccines work, what benefits and side effects to expect, how to make practical decisions about timing and eligibility, and how to evaluate vaccine claims using high-quality evidence.