It was discovered that administering weakened culture of the disease causing micro-organisms to a healthy animal induced immunity to that particular disease. Such diseases include whooping cough, rabies, tuberculosis, rubella, poliomyelitis, measles, mumps, and diphtheria. Recently, scientists developed a vaccine against Hemophilic influenza, type B (Hib) which is the foremost cause of meningitis that results in death or brain damage