In 1798, when Edward Jenner discovered the first vaccine -- it happened to be for smallpox -- he didn't just discover a prophylactic for a disease, but a whole new way of thinking: that medicine could prevent disease.
El 1798, quan Edward Jenner  va descobrir la primera vacuna -- que va ser per la verola -- no va descobrir només  un profilàctic per una malaltia, sinó tota una manera nova de pensar: que la medicina podia prevenir la malaltia.