Ohio mumps outbreak grows

The mumps outbreak in central Ohio now totals 225 cases, state health officials in Columbus reported late Tuesday.

A majority of the reported cases — 139, or 62% — have been linked to Ohio State University, says Julie Mangino, director of the Department of Clinical Epidemiology for the OSU Health System, and a member of the university's Mumps Advisory Executive Team.

The university confirmed its first cases, involving fewer than 10 students, in late February, Mangino says. "Normally in Franklin County, where the OSU Wexner Medical Center and the university are located, we have one case of mumps a year. So this is very unusual."

New cases are continuing to be reported, with one as recently as April 14, "so I am concerned that we may not be at a plateau yet," she says.

National case counts are typically several hundred a year, says the Centers for Disease Control and Prevention. It reported 438 cases of the mumps in 2013. A multistate mumps outbreak involving more than 6,500 reported cases, largely college-aged students living on different Midwestern college campuses, occurred in 2006.

In addition to Ohio State, Fordham University in New York reported a significant number of cases this year.

In the central Ohio outbreak, the infected range in age from 9 months to 70 years old. Most of the cases (62%) involve females (140 cases). There have been few hospitalizations, with most patients recovering on their own within four to five days, says Melanie Amato, spokeswoman for the Ohio Department of Health.

Mumps is a contagious disease spread through the saliva or mucus from the mouth, nose or throat of an infected person, usually when that person coughs, sneezes or talks.

According to the CDC, a major factor contributing to outbreaks is commingling in a crowded environment, such as attending the same class, playing on the same sports team or living in a dormitory with someone who has mumps.

Initial symptoms include fever, headache, muscle aches, fatigue and loss of appetite, followed by swelling of the salivary glands under the ears or jaw, according to the CDC.

Although most people with the mumps recover fully, the agency says it sometimes leads to serious problems such as hearing loss, meningitis and swelling of the testicles in males or the ovaries in females (if the affected male or female has gone through puberty).

In response to the outbreak, Ohio state health officials have stressed the importance of vaccinations, both for individuals who have not received any doses of the measles-mumps-rubella (MMR) vaccine as well as those who have received only one dose.

"Immunization is the most effective way to protect yourself and your family from vaccine-preventable diseases," Ohio Department of Health epidemiologist Mary DiOrio says in a statement. "In addition, to reduce the spread of infectious diseases, such as mumps, wash your hands often, cover your cough, and stay home when you are ill," she says.

Although the mumps vaccine provides good protection, it's long been known that it's not as effective as the vaccines against measles and rubella, says William Schaffner, an expert in infectious diseases at Vanderbilt University School of Medicine in Nashville.

According to the CDC, two doses of mumps vaccine protect about 88% of people from the disease. One dose protects 78%. CDC recommends babies get two doses.

"Yes, you can get mumps after being vaccinated, and "that's due to waning immunity," says Mangino, noting that the antibodies the vaccine makes to fight infection may decline over time.

A review of health records at OSU showed that 97% of those diagnosed with the mumps on campus had had their MMR vaccines, she says.

A better vaccine needs to be developed for use in the USA, Schaffner says. Until then, it's especially important to vaccinate nearly everyone, a practice that causes "herd immunity," in which vaccinated people prevent disease from circulating, he says.

Even with a less-than-ideal mumps vaccine, the U.S. has mostly kept the disease in check through high vaccination rates. Before the widespread introduction of the vaccination in 1967, about 186,000 cases were reported annually, most often in infants, children and young adults. The CDC says that figure has since decreased by more than 99%.

Contributing: Liz Szabo