Vaccination is a preventive measure that involves administering a vaccine to stimulate the immune system to produce a specific response against a pathogen, such as a virus or bacteria. This response prepares the body to defend itself against future infections by that same pathogen. Vaccinations have been instrumental in reducing the burden of infectious diseases and have led to the eradication of diseases such as smallpox. Vaccination research focuses on the development of new vaccines, improving existing vaccines, understanding immune responses to vaccines, and addressing issues related to vaccine hesitancy and acceptance.