Before the widespread use of a vaccine against measles, its incidence was so high that infection with measles was felt to be "as inevitable as death and taxes."[3] Today, the incidence of measles has fallen to less than 1% of people under the age of 30 in countries with routine childhood vaccination.[citation needed]
The benefit of vaccination against measles in preventing illness, disability, and death has been well-documented. The first 20 years of licensed measles vaccination in the U.S. prevented an estimated 52 million cases of the disease, 17,400 cases of mental retardation, and 5,200 deaths.[4] During 1999–2004, a strategy led by the World Health Organization and UNICEF led to improvements in measles vaccination coverage that averted an estimated 1.4 million measles deaths worldwide.[5]
Measles is endemic worldwide. Although it was declared eliminated from the U.S. in 2000, high rates of vaccination and good communication with persons who refuse vaccination is needed to prevent outbreaks and sustain the elimination of measles in the U.S.[6] Of the 66 cases of measles reported in the U.S. in 2005, slightly over half were attributable to one unvaccinated individual who acquired measles during a visit to Romania.[7] This individual returned to a community with many unvaccinated children. The resulting outbreak infected 34 people, mostly children and virtually all unvaccinated; 9% were hospitalized, and the cost of containing the outbreak was estimated at $167,685. A major epidemic was averted due to high rates of vaccination in the surrounding communities.[6]
Mumps is another viral disease of childhood that was once very common. If mumps is acquired by a male who is past puberty, a possible complication is bilateral orchitis which can in some cases lead to sterility.[8]
Rubella fell sharply when immunization was introduced.Rubella, otherwise known as German measles, was also very common before the advent of widespread vaccination. The major risk of rubella is if a pregnant woman is infected, her baby may contract congenital rubella from her, which can cause significant congenital defects.[9]
All three diseases are highly contagious.