Max Theiler health at the Yale School of Medicine and the School of Public Health from 1964 to 1967. After passing the yellow fever virus through laboratory mice, Theiler found that the weakened virus conferred immunity on rhesus macaques. The stage was set for Theiler to develop a vaccine against the disease. Theiler first devised a test for the efficacy of experimental vaccines. In his test, sera from vaccinated human subjects were injected into mice to see if they protected the mice against yellow fever virus. This "mouse protection test" was used with variations as a measure of immunity until after World
Vaccine vaccine is designed to immunize against a single antigen or single microorganism. A multivalent or polyvalent vaccine is designed to immunize against two or more strains of the same microorganism, or against two or more microorganisms. The valency of a multivalent vaccine may be denoted with a Greek or Latin prefix (e.g., "tetravalent" or "quadrivalent"). In certain cases, a monovalent vaccine may be preferable for rapidly developing a strong immune response. Also known as heterologous or "Jennerian" vaccines, these are vaccines that are pathogens of other animals that either do not cause disease or cause mild disease in the organism