Vaccines

Vaccines are biological preparations administered to prevent disease or lessen disease severity, and the process of administering a vaccine to an individual is called vaccination. There are several types of vaccines, but all operate on the principle of introducing an antigen (for instance, the virus that causes measles) in a weakened or inactivated state into an individual’s body for the purpose of stimulating the individual’s immune system to produce antibodies against that antigen. In this way, vaccines make recipients immune or less susceptible to the disease caused by that antigen (in this case, measles), thus protecting them from the health consequences of becoming infected with that disease. Vaccination is an important public health measure and has led to widespread reduction in the occurrence of many ...