A vaccine is a biological preparation that trains the immune system to recognize and protect against specific infectious diseases without causing the disease itself.
Vaccines work by safely exposing the immune system to all or part of a disease-causing organism, or to instructions that allow the body to produce a harmless component of it. This stimulates the production of immune cells and antibodies, creating immune memory that helps the body respond rapidly if exposed to the real infection in the future.
Vaccination has dramatically reduced or eliminated many serious diseases, including smallpox, polio, measles, and tetanus, and remains one of the most effective public health interventions.
Different vaccines use different technologies and may require multiple doses or periodic boosters.
QUICK FACT
- Vaccination does not guarantee that infection can never occur; depending on the vaccine and disease, it can substantially reduce infection, severe disease, complications, or transmission.
- Smallpox is the only human infectious disease to have been eradicated worldwide through vaccination.
COMMONLY CONFUSED WITH
- Vaccination: the act or process of administering a vaccine.
- Immunity: the body’s ability to recognize and respond to a particular threat; vaccination is one way of developing immunity.
- Medication: Vaccines help prevent disease before it occurs, whereas most medications are used to treat disease after it develops.
SEE ALSO