NEW YORK - So far this year, nearly 6,000 cases of mumps have been reported to the US Centers for Disease Control and Prevention, reinforcing the importance of the MMR vaccine, particularly in high-risk populations, such as healthcare workers and college students.

The MMR is a 3-in-1 vaccine that protects against measles, mumps and rubella (German measles), which is usually administered between 12 and 15 months of age and again between 4 and 6 years of age. In general vaccination required before a child can be admitted to school.

From January 1 to October 7, 2006, a total of 5,783 confirmed or probable cases of mumps from 45 states and the District of Columbia occurred, according to findings released Thursday in the CDC's Morbidity and Mortality Weekly Report.

The bulk of cases, 84 percent, came from just 6 states. Iowa reported the most, followed by Kansas, Wisconsin, Illinois, Nebraska, and South Dakota.

The average patient age was 22 years and 63 percent of patients were female. Consistent with earlier reports, the highest age-specific rate of mumps was in people between 18 and 24 years of age, including many college students.

A peak in mumps cases was seen in the last two weeks of April, and from May until September a steady drop in reported cases occurred. However, as students began returning to school toward the end of August, mumps clusters at colleges in three states have been reported.

In response to the large number of mumps cases this year, the Advisory Committee on Immunization Practices updated its vaccination recommendations.

"To ensure high levels of immunity, especially among groups at high risk for exposure and infection, every opportunity should be used to provide the first or second dose of MMR vaccine to those without adequate evidence of immunity."

The authors of the report suggest that MMR vaccine could be offered in conjunction with influenza vaccination.