Vaccine Histories and Impact on Diseases – Do disease cases and deaths drop once a vaccine against the disease is introduced? How and when were vaccines discovered and developed? What does the CDC recommend? What is the vaccination rate for childhood vaccines? Find the answers to these questions about diphtheria, tetanus (lockjaw), pertussis (whooping cough), polio, measles, mumps, rubella, hepatitis B, Hib, and varicella.