There have been, and continue to be, many breakthroughs over the course of vaccine development—an endeavor that began more than 200 years ago and continues to this day. Before the types of vaccines we use in modern times could be developed, researchers had to study diseases to find out what caused them; how they were transmitted; what effects they had on the human body; and how the human immune system reacted to them.

This timeline highlights the discoveries and breakthroughs that have allowed the human race to fight back against smallpox, polio, the measles, yellow fever and a host of other diseases that were once widespread throughout the world. It includes the development of the steps used to identify the agent causing a disease; the experiments that proved mosquitoes were the transmission vector for yellow fever; and the discovery that cowpox could protect against smallpox—the first vaccine in history.


Jenner's Breakthrough

Edward Jenner vaccinated a boy and demonstrated that he was protected from smallpox. More

Loeffler’s Contributions

Loeffler’s work on diphtheria led to the formulation of Koch’s Postulates. More

Measles Virus Isolated

In 1954, Thomas Peebles successfully isolated the virus responsible for measles. More