In a study reported in the April 10 issue of the New England Journal of Medicine, authors urge a more effective mumps vaccine or changes in vaccine policy to eradicate the disease.
The study found that 84 percent of people between the ages of 18 and 24 who became ill in the outbreak had received the second recommended dose.
The national incidence of mumps was 2.2 per 100,000. The highest incidence was in persons 18 to 24 years of age, with an incidence 3.7 times that of all other age groups combined.
"Despite a high coverage rate with two doses of mumps-containing vaccine, a large mumps outbreak occurred, characterized by two-dose vaccine failure, particularly among Midwestern college-age adults who probably received the second dose as schoolchildren," the study authors wrote. "A more effective mumps vaccine or changes in vaccine policy may be needed to avert future outbreaks and achieve the elimination of mumps."
The authors conclude that further studies are needed to help evaluate national vaccine policy, including whether the administration of a second dose of MMR [measles-mumps-rubella] vaccine at a later age or the administration of a third dose would provide higher or more durable immunity.
Mumps is a disease caused by a virus that usually spreads through saliva and can infect many parts of the body, especially the parotid salivary glands. These glands, which produce saliva for the mouth, are found toward the back of each cheek, in the area between the ear and jaw. In cases of mumps, these glands typically swell and become painful.
Mumps was common until the mumps vaccine was licensed in 1967. Before the vaccine, more than 200,000 cases occurred each year in the United States. Since then the number of cases has dropped to fewer than 1,000 a year, and epidemics have become fairly rare.
