Consumer Reports

Mumps is on the rise in some parts of the U.S., and some public-health professionals are wondering whether the current vaccine is working as well as it needs to.
Cases of mumps hit a 10-year high near the end of 2016 with 5,748 cases reported, and the surge has continued into 2017.
Between January 1 and late March, nearly 2,000 mumps infections across 42 states and the District of Columbia were reported to the Centers for Disease Control and Prevention.     Over a whole year nationwide, 200 to 2,000 cases is more typical, according to the CDC.
The Arkansas Department of Health was investigating close to 3,000 suspected or confirmed cases as of April 21. Washington State health officials say the state has had more than 600 likely or confirmed cases between early January and April 19. Texas noted 221 mumps infections from early January through mid-April. There are also recent outbreaks in Illinois, Iowa, Kansas, Minnesota, Missouri, Pennsylvania, New York, and Oklahoma, among other states.
In some areas, health experts have recommended a mumps booster vaccine. During World Immunization Week, here’s what you need to know about the outbreaks and who might consider this shot.
Outbreaks Among the Immunized
A once-common contagious illness, the mumps can bring temporary but painful swelling of the salivary glands in the jaw, and complications such as swelling of the testicles or ovaries, or in rare instances, inflammation of the brain.
Most people recover fully within a few weeks, but occasionally, says the CDC, it can lead to sterility in men or long-term cognitive and physical disabilities.
The best protection is immunization via the two-dose measles, mumps, and rubella (MMR) vaccine given early in childhood. The two doses confer about 88 percent protection against mumps.
But many of the recent outbreaks have taken place in communities where most people are up-to-date on their immunizations. While experts are unsure what’s causing the current spike in those areas, some theorize that it could be the result of a mumps strain that isn’t well covered by the current vaccine.
Others are examining whether the two-dose MMR provides enough protection to last through adulthood.
Changing Strains, Waning Immunity
Could the MMR be failing to guard against newer mumps strains? According to Janell Routh, M.D., a medical epidemiologist at the CDC’s Division of Viral Diseases, it’s unlikely. That’s because the dominant subtype of the virus, which the MMR targets, hasn’t changed since the CDC started lab surveillance of mumps outbreaks in 2006.
But the long-held assumption that the MMR’s protection is lifelong might not be entirely true. After 10 to 15 years, effectiveness against the mumps may diminish, according to William Schaffner, M.D., a professor of preventive medicine at Vanderbilt University in Tennessee.
And close living quarters, such as college dorms—where a large number of immunized young adults can have prolonged and intense exposures to the mumps virus—create an ideal environment for an outbreak, he says.
Booster Basics
In an effort to curb outbreaks, some colleges and local communities that have experienced an increase in mumps have offered a booster to residents.
For instance, an outbreak at the University of Missouri that began last fall prompted the school—in consultation with local and state health departments and the CDC—to recommend a third dose of MMR to students, says Susan Even, M.D., executive director of the university’s Student Health Center.
And if you live or work at a college or in a community hit by an outbreak, you may want to consider this, says Schaffner: “There’s no harm other than a sore arm, and you might incur some benefit. It’s a perfectly reasonable step to take.”
But most people, says Schaffner, probably don’t need one. And it’s not yet clear that a third dose of MMR provides more robust protection than two, although the CDC is studying the issue closely, says Routh.
In the interim, make sure that you’re up-to-date on your MMR; people who are fully vaccinated and contract the mumps are less likely to develop severe complications, says Routh.
If you never had the mumps and didn’t get the MMR as a child—or don’t remember—you can get vaccinated now. The CDC recommends one dose of MMR for adults who haven’t had the vaccine, two doses if you’re an adult at higher risk, such as a healthcare worker, an international traveler, or a college student.
If you’ve already had mumps—or were born before 1957 —you’re considered immune; it’s rare for mumps to recur.
In addition, take these steps to protect yourself and others from mumps:

• Wash your hands often. Wet your hands with water, work soap into a lather and scrub for at least 20 seconds. If the mumps virus is on your hands, this helps prevent it from spreading.
• Don’t share. “That includes food, drink, lipstick, utensils—just don’t do it,” says Even. Mumps spreads by saliva and respiratory droplets that can cling to a variety of surfaces.
• If you have the mumps, stay home. If you think you might have mumps, stay home in isolation for the five or so days you have symptoms (and note that some people have only mild or non-specific symptoms such as body aches, fatigue, and fever). Call your doctor if you experience a puffy jaw or swelling on any other part of your body. You may require medical treatment.