From Smallpox to COVID: Vaccines that Changed History

The field of public health was transformed by the introduction of vaccination, from the Latin word “vacca” meaning cow, to guard people against infectious diseases. It was well known that exposure to infectious diseases and surviving them conferred some natural immunity against subsequent outbreaks. Pioneers in the use of vaccinations included Edward Jenner, Louis Pasteur, and Gaston Ramon, and their work ensured many of the world's deadliest diseases could finally be tamed.