“Arabian smallpox maliciously undermines man at the threshold of life and preys on the human species almost destroying it in its birth. This very sad thought is exacerbated by the repeated heavy losses of life caused by the disease and should persuade everyone to embrace with great enthusiasm and receive with equal gratitude the inoculation vaccine, a method that is as simple as it is effective in curbing the poisonous force of the disease.”
These words are from the Edict on Vaccination, June 20, 1820, issued immediately after an epidemic of smallpox in the Papal States by the Secretary of State, Cardinal Ercole Consalvi, on behalf of Pope Pius VII. It provided, in case of epidemics, organizational measures of public health (quarantine, isolation) and the practice of vaccination (administration, records, certificates, supply), making it mandatory and free.
The British physician Edward Jenner (1749-1823) had confirmed, in 1798, the safety and efficacy of the procedure that used cowpox to treat the more serious smallpox. Those who came into contact with the bovine form of smallpox did not contract smallpox, obtaining what we now call immunization.