WASHINGTON - The college years seem to be a prime time for coming down with the mumps.
This spring, outbreaks of mumps have been reported at three universities in Virginia: the University of Richmond, Virginia Commonwealth University and James Madison University. Cases have also been reported at Loyola University in Baltimore.
The outbreaks at area college campuses are part of a national pattern, says Dr. David Hyun, an infectious disease specialist at Children's National Medical Center.
"The outbreaks that we have seen in the past few years tend to come from college students," he says, adding the prime age for mumps now seems to be 15 to 24.
No one is exactly sure why. But Hyun says the mumps vaccine could be losing its effectiveness over time.
"I don't think we know exactly how long our immunity from our childhood immunizations gives us adequate protection against mumps," he says. "There is ongoing research looking at that exact question and trying to come up with answers."
The mumps vaccine was developed in the late 1960s and recommended for routine childhood immunization a decade later. But it wasn't until the 1990's that schools began to require it. The inoculation is typically mixed with vaccines to protect children against measles and rubella.
That means data is just starting to come in on the long-term protection provided by the mumps vaccine, enabling researchers to get a feel for whether some kind of booster shot might be necessary.
This is the same scenario that played out a few years ago with the pertussis, or whooping cough, vaccine.
Originally just recommended for small children, the Centers for Disease Control and Prevention now recommends a booster shot for tetanus, diptheria and pertussis for pre-teens.
"They determined that the protection level was not adequately extending itself past the second decade of life," Hyun says.
He notes that when vaccines first come out, it is difficult to figure out those kinds of limitations. He says it takes a lot of data and the passage to time to understand when protection might begin to fade.
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