A mumps outbreak at San Diego State University has grown to 14 confirmed cases and one probable case, up from five confirmed and probable cases reported two weeks ago.
In an email sent Wednesday, Dr. T. Ghosh, Medical Director of SDSU Student Health Services, said the cases remain connected to a single student athletic team and one associated case outside the team.
The university has not publicly identified the team involved. The San Diego Union-Tribune reported it’s the football team.
The update on the outbreak comes days before the Aztecs are scheduled to play Texas State on Saturday at Snapdragon Stadium in their first Pac-12 game of the season.
San Diego County public health officials said everyone confirmed to have a mumps infection had previously received two doses of the measles, mumps and rubella, or MMR, vaccine.
So how can mumps spread among people who have been vaccinated?
Dr. George Sakoulas, an infectious disease specialist with Sharp Memorial Hospital, said two doses of the vaccine is still effective, but protection can decrease over time.
“If you look at people who've gotten the vaccine in the last two years compared to people who got the vaccine 20 years ago, the rates of getting mumps is about tenfold less,” Sakoulas said.
He said waning immunity can be addressed during an outbreak with an additional vaccine dose.
“You try to get through by kind of providing a little bit of a booster in that local environment where that outbreak is happening,” he said.
Ghosh said the university is offering an additional MMR dose to members of the affected team and other people identified as close contacts. They will continue screening, testing and contact tracing the affected students, Ghosh said.
Sakoulas said the close-contact environment of a sports team can also help the virus spread.
“They travel together, they get in buses together, certainly in their locker rooms, they probably hang out together after practice,” he said.
Mumps spreads through respiratory droplets, and symptoms can take days or weeks to appear.
Sakoulas said people can spread the virus before they realize they are sick.
“The first two or three days, they feel like, ‘oh, I got a headache and a little bit of a fever, I may have the flu, I may have something else, OK, I'll plow through it,’” he said. “It's not till a couple of days later where your salivary glands swell up, and by that point, you've probably been shedding virus for three, five, seven days.”
For male athletes, Sakoulas said there's another complication to watch for.
“About a quarter to a third of males postpuberty who get mumps can again get a very, very painful orchitis, which is a testicular pain.”
The County’s Public Health Department says there are no confirmed or probable cases outside those associated with SDSU at this time and it is continuing to monitor the outbreak.
Anyone who develops symptoms should stay home, avoid close contact with others and call a healthcare provider, SDSU says.
The university is offering a free MMR booster clinic on campus on Thursday, Oct. 1, from 10 a.m. to 2 p.m.
