How does someone become infected with measles, mumps, rubella and varicella?
All four infections are caused by viruses that are spread through person-to-person contact or rarely are airborne spread. How effective is the MMRV vaccine? When both doses of the MMRV vaccine are given, the immunized recipient is thought to be at least 95 percent protected from measles, rubella and varicella and 85 percent protected against mumps. Since the measles vaccine was licensed, there has been a 99 percent reduction in measles cases in the United States. With the introduction of the mumps vaccine, the annual number of mumps cases has fallen from approximately 200,000 cases to 600 cases. However, in 2006 outbreaks of mumps in adolescents and adults were reported from several states. Before a vaccine was developed for rubella, there was a rubella outbreak in the United States from 1963 to 1964, and 12 million people contracted the disease. More than 11,000 fetuses died, and 20,000 babies were born with birth defects. Today, fewer than 25 cases of rubella are reported in the Unit
