A vaccine is a biological preparation intended to improve immunity to a disease by stimulating the production of antibodies. Vaccines typically contain small amounts of killed or attenuated microorganisms, or their derivatives. They aim at preventing or ameliorating the effects of infection. The first successful vaccine to be developed was smallpox vaccine. Its inventor – Edward Jenner, an English scientist – observed that milkmaids who caught the cowpox virus did not develop smallpox. Jenner is renown as the „father of immunology”.