Effectiveness
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." Today, the incidence of measles has fallen to less than 1% of people under the age of 30 in countries with routine childhood vaccination. Reported cases of measles in the United States fell from hundreds of thousands to tens of thousands per year following introduction of the vaccine in 1963. Increasing uptake of the vaccine following outbreaks in 1971 and 1977 brought this down to thousands of cases per year in the 1980s. An outbreak of almost 30,000 cases in 1990 led to a renewed push for vaccination and the addition of a second vaccine to the recommended schedule. Fewer than 200 cases have been reported each year since 1997, and the disease is no longer considered endemic.
The benefit of measles vaccination 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. 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.
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. 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. 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.
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.
Rubella, otherwise known as German measles, was also very common before the advent of widespread vaccination. The major risk of rubella is in pregnancy. If a pregnant woman is infected, her baby may contract congenital rubella from her, which can cause significant congenital defects.
All three diseases are highly contagious.
The combined MMR vaccine was introduced to induce immunity less painfully than three separate injections at the same time, and sooner and more efficiently than three injections given on different dates.
In 2012, the Cochrane Library published a systematic review of scientific studies. Its authors concluded, "Existing evidence on the safety and effectiveness of MMR vaccine supports current policies of mass immunisation aimed at global measles eradication and in order to reduce morbidity and mortality associated with mumps and rubella."
Read more about this topic: MMR Vaccine