This is why the mumps is making a comeback in Delaware

If you think you're immune to the mumps because of the vaccinations you received as a child, think again.  

The mumps has made its way back to Delaware — and can still infect those who are immunized, doctors say. 

This is the first time in at least a decade that Delaware has experienced an outbreak of this kind. Eleven people, including a 1-year-old child, have been confirmed as having the illness as of Monday morning, though health officials believe this number is likely higher. 

Doctors attribute the outbreak to several causes, including the disease being highly contagious, spreading quickly among close-contact communities. They say the vaccination for it, which children receive twice in childhood, also doesn't always protect people from getting the mumps, making some infectious disease experts believe the effectiveness wanes over time.

That has caused a group of Harvard researchers to recently recommend people get a third dose of the shot when they turn 18. 

None of the experts blame the outbreaks around the country on people who decide not to vaccinate their children at all.

State health officials say this year's outbreak started after a Mexican dance at the Chase Center on the Riverfront in February. One person confirmed with having the mumps attended a dance a month later at the same location, the state said.

The outbreak in Delaware has spread to Chester County in Pennsylvania. The county health department confirmed 19 cases as of March 28. 

Decades ago, it was common for the U.S. to have more than 186,000 cases of the mumps a year, according to the Centers for Disease Control and Prevention. With the creation of the measles, mumps and rubella vaccination, these numbers have dwindled.

Even so, in recent years the CDC has seen a substantial increase in the number of mumps cases in the U.S., going from 229 cases in 2012 to 6,366 cases in 2016. 

"It’s exceedingly rare to die from the mumps," said Dr. Awele Maduka-Ezeh, medical director of the Delaware Division of Public Health. "There can be serious complications.

"It's not something we play around with."

Making a comeback

More than 50 years ago, the mumps was a condition that was, for many, a staple of childhood.

Best known for causing puffy cheeks and swollen jaws, the most common symptom of the highly contagious disease is swollen salivary glands. Other common symptoms include fever, headache, muscle aches and loss of appetite.  

The creation of the MMR vaccine helped reduce mumps cases by 99 percent in the United States, CDC officials said. In the past decade, the CDC has noticed a rise in mumps outbreaks.

Because of this, some local doctors aren't surprised to find mumps in Delaware. 

"This has been expected and seen unfortunately since 2006," said Dr. Craig Shapiro, an infectious disease specialist at Nemours/A.I. DuPont Hospital for Children. One of the first modern outbreaks of mumps occurred in 2006 at several Midwest college campuses, involving more than 6,500 people.

There hasn't been an outbreak of the mumps in Delaware since at least 2005, state health officials said. 

Mumps outbreaks tend to occur in close-contact communities where young people live, such as schools, college campuses and camps. Kissing or sharing utensils, cups, lip balm or cigarettes is known to accelerate the spread of the virus.

State health officials said about 2,000 people attended the Feb. 10 Mexican dance and 1,500 people attended the March 3 event. 

While the vaccination can help prevent the spread of the disease and limit its intensity, it doesn't always create immunity to the disease, doctors say. The CDC recommends children get the first dose of the MMR vaccine between 12 to 15 months of age and the second dose between ages 4 to 6 years old.

Two doses of the MMR vaccine is about 88 percent effective while one dose is about 78 percent effective, CDC officials said.

Dr. Thomas Fekete, interim chair of the Department of Medicine at the Lewis Katz School of Medicine at Temple University, said of the three diseases the vaccine protects against, the mumps vaccine has the least-effective immunity. 

Compared to other viruses, such as the flu, mumps isn't circulating most of the time, he said. When people do get it, it's often because of exposure and not having immunity. 

“Even if you were zooming in from planet Krypton, you probably wouldn't get mumps having zero immunity," Fekete said. "But if you’re unlucky enough to come from planet Krypton during an outbreak, you probably will get it because it’s pretty contagious."

Shapiro, the Nemours physician, attributes this to the vaccine being developed in 1967. The genotypes of the circulating strains are slightly different than the strain that was used develop the vaccine more than 50 years ago. Since the vaccine hasn't been altered over the decades, it's not a 100 percent match, though it is still "very good," he said.

While the condition isn't life-threatening, mumps can lead to serious complications, Fekete said. This includes inflammation of testicles, ovaries, breast tissue, the brain and tissue covering the brain and spinal cord.

There's no treatment for the mumps, he said. Doctors recommend people who have the condition, or believe they have it, should stay home from work or school until five days after first feeling swollen glands.

He believes mumps will "probably be around for a very long time" unlike other viruses.

"It might happen eventually, and it would be great if it did happen, but I'm not sure we're aiming for that partly because it's just one of those things," Fekete said.

"It’s not that urgent."

Third times the charm?

With mumps cases on the rise in the United States, researchers and doctors are looking into the idea of whether people should get a third vaccine when entering adulthood.

Harvard researchers estimated that 50 percent of people in the U.S. vaccinated against the mumps may lose protection within 19 years of getting the immunization.

They said waning immunity has "played a central role not only in the recent re-emergence of mumps cases among young adults but also in outbreaks that occurred in the late 1980s among adolescents who had received only one dose under earlier recommendations," according to a news release. 

Because of this, the researchers recommended a booster shot at age 18 to help avoid future outbreaks. 

This fall, the CDC changed its policy to recommend a third shot when an outbreak occurs. 

Right now, the Delaware health department is following the CDC's recommendation, particularly for friends and family members of people who have the infection, Maduka-Ezeh said.

She recommends residents reach out to their physicians if they think they have the mumps or came in contact with some who has the virus. 

Fekete, the Temple physician, said if people are concerned about getting the mumps, they can ask their doctor about getting a third vaccination. But he doesn't believe the third shot will become a "big ticket item."

While an additional vaccine could protect millions from the "small, but real chance" of developing the mumps in adulthood, it would likely protect "maybe 100 people a year," he said. 

"That’s really what the question is," he said. "Not that it works, we believe it to work, but whether it's worthwhile."

Contact Meredith Newman at 302-324-2386 or at mnewman@delawareonline.com. Follow her on Twitter at @merenewman.

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