This document discusses the history and development of vaccinations. It notes that the first vaccines were created in 1796 for smallpox, and since then vaccines have been developed for many other diseases like polio, measles, and mumps. It also lists over 20 diseases for which vaccines have been created. The document explains how vaccines work by using weakened or killed strains of viruses or bacteria to allow the immune system to develop antibodies without causing illness. Finally, it acknowledges some common criticisms of vaccinations but does not take a position on their validity.