Vaccine for yellow fever

Dr. Max Theiler discovered in 1930 that white mice are susceptible to yellow fever virus inoculated intra-cerebrally and that serial intra-cerebral passage of the virus in this host produces a loss of virulence for monkeys.

This observation revealed for the first time the possibility of protecting exposed human beings against attacks of this dread disease. It led almost at once to a method of human vaccination against yellow fever which is still extensively used. Further work by Dr. Theiler, in 1936 and 1937, resulted in the production of a more profound modification of the virus by means of prolonged maintenance in tissue cultures. This strain of virus, known as 17D, has been made the basis of another effective vaccine utilized for the protection of millions of human beings against yellow fever in various parts of the world.