vaccinated

Vaccinated is an adjective used to describe a person who has received a vaccine, or a population with documented vaccination against a disease. Vaccination is typically part of public health programs and individual health care, and the term depends on the vaccine and the schedule followed.

Vaccines introduce a harmless form of a pathogen, or a component of it, to stimulate an immune response. The immune system then develops memory cells and antibodies that can reduce the risk of infection or lessen the illness if exposure occurs.

Vaccination has dramatically reduced the incidence of many infectious diseases and contributed to the eradication or control of several pathogens. High coverage in a population can protect those who cannot be vaccinated through herd immunity. Historical examples include smallpox eradication and substantial declines in measles and polio in many regions.

Vaccination status is documented on immunization records or certificates and may be required for school enrollment, travel, or employment. Some vaccines require multiple doses or boosters to maintain protection, and recommendations vary by age, health status, and location.

Vaccine safety monitoring systems track adverse events after vaccination. Most reactions are mild, such as soreness at the injection site or low fever; serious adverse events are rare. Public health organizations base guidance on ongoing evaluation of risks and benefits.