A vaccine is an immunity booster to a certain disease. The term derives from Edward Jenner's use of cowpox ("vacca" means cow in Latin), which, when administered to humans, provided them protection against smallpox, the work which Louis Pasteur and others carried on. Vaccines are based on the concept of variolation originating in China, in which a person is deliberately infected with a weak form of smallpox. Jenner realized that milkmaids who had contact with cowpox did not get smallpox. The process of distributing and administrating vaccines is referred to as vaccination. Since vaccination was much safer, smallpox inoculation fell into disuse and was eventually banned in England in 1848. Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic (e.g. vaccines against cancer are also being investigated; see cancer vaccine). Types of vaccines vaccine