Midwestern Mumps Outbreak Should Heighten FPs' Index of Suspicion

Iowa, a state that typically conjures up images of nothing more sinister than gently waving cornfields, now has the dubious distinction of being ground zero for an outbreak of mumps that is rapidly spreading throughout the Upper Midwest. Family physicians should heighten their suspicion for the disease in patients who present with its hallmark parotitis, says one FP expert.

Through April 12, a total of 605 probable, confirmed and suspected mumps cases had been reported to the Iowa Department of Public Health, according to an update from the department's Center for Acute Disease Epidemiology (PDF file: 2 pages / 65 KB. More about PDFs.). Mumps activity also is being investigated in six neighboring states -- Illinois (four cases), Kansas (33), Minnesota (one), Missouri (four), Nebraska (43), and Wisconsin (four) -- says a Morbidity and Mortality Weekly Report Dispatch posted April 11. As of April 14, unpublished data from the CDC put the number of affected states at eight, adding Indiana and Michigan.

Iowa public health officials recently identified two potentially infectious individuals who traveled on nine commercial flights to destinations in some of those states and others -- including Arizona, Arkansas and Texas -- between March 26 and April 2.

"What's remarkable here is the rapidity with which an epidemic can proceed with modern forms of travel," says FP Doug Campos-Outcalt, M.D., M.P.A., an AAFP liaison to the CDC's Advisory Committee on Immunization Practices and a former chair of the AAFP's Commission on Clinical Policies and Research. "This emphasizes the need to keep immunizations up-to-date even if your area has not seen a particular disease for a while. This is no time for complacency."

Indeed, appropriate immunization is key to preventing or ameliorating outbreaks of preventable diseases such as mumps, according to Jonathan Temte, M.D., Ph.D., an associate professor in the family medicine department at the University of Wisconsin, Madison, and the AAFP's other liaison to the CDC immunization advisory committee.

"This is a reminder that immunization is an ongoing need," says Temte. "Even when diseases are apparently vanquished -- or at least subdued -- it takes very little for them to re-emerge."

The two-dose measles-mumps-rubella immunization schedule confers immunity in about 95 percent of those vaccinated; a single MMR dose produces a reduced level of immunity. Some patients may not have received MMR vaccine at all, so it's not completely unexpected to see such an outbreak, given the extreme contagiousness of the disease, say CDC officials and other infectious disease experts. "In Iowa, approximately 68 percent of cases did have reported two-dose MMR," Temte notes.

The 2006 Recommended Childhood and Adolescent Immunization Schedule (PDF file: 2 pages / 145 KB. More about PDFs.) developed by the CDC, AAFP and the American Academy of Pediatrics notes that the first dose of MMR should be administered at the 12-month (preferred) or 15-month visit. The schedule recommends routine administration of the second dose between ages 4 and 6 years, although it may be administered at any subsequent visit provided that at least four weeks have passed since administration of the initial dose and both doses are given on or after age 12 months. The two-dose schedule should be completed by age 11 or12.

The Recommended Adult Immunization Schedule for 2005-06 (PDF file: 4 pages / 234 KB. More about PDFs.) shows the appropriate MMR schedule for those who did not complete the two-dose series or who are uncertain about their immunization status. The schedule notes that caution is required when considering immunization of women of childbearing age; women who are pregnant or who may become pregnant within four weeks of receiving the vaccine should not be immunized because of the risks posed to the fetus by the rubella component of the vaccine.

Temte emphasizes these four takeaways:

Visit the National Immunization Program's "Recent Mumps Outbreaks" page for the latest information gathered by the CDC on this topic.