Vaccination is the administration of antigenic material (a vaccine) to stimulate an individual’s immune system to develop adaptive immunity to a pathogen. Vaccines can prevent or ameliorate morbidity from infection. The effectiveness of vaccination has been widely studied and verified; for example, the influenza vaccine, the HPV vaccine, and the chicken pox vaccine.

Medical and scientific evidence surrounding vaccination demonstrates that the benefits of preventing suffering and death from infectious diseases far outweigh rare adverse effects of immunization. Despite this, vaccination controversies began almost 80 years before the terms vaccine and vaccination were introduced and continue to this day.

Opponents have claimed that vaccines do not work, that they are or may be dangerous, that individuals should rely on personal hygiene instead, or that mandatory vaccinations violate individual rights or religious principles. These arguments have reduced vaccination rates in certain communities, resulting in epidemics of preventable, and sometimes fatal, childhood illnesses.

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Image: Child receiving an oral polio vaccine in India. Source: Stop Transmission of Polio (STOP)