WEDNESDAY, Oct. 31 (HealthDay News) -- With intense exposure to the mumps virus, even some vaccinated people may still contract the disease, researchers say.
That's what health experts believe happened in several Orthodox Jewish communities that experienced an outbreak of the mumps a couple of years ago.
"From June 2009 through June 2010, the U.S. experienced large mumps outbreaks in several large Orthodox Jewish communities, primarily among people who were well vaccinated," said Albert Barskey, an epidemiologist in the division of viral diseases at the U.S. Centers for Disease Control and Prevention.
Barskey is the lead author of a report detailing the outbreak, published in the Nov. 1 issue of the New England Journal of Medicine.
By 2005, the vaccination rate for mumps was more than 99 percent in the United States, according to the CDC. Although few outbreaks were reported at that time, an outbreak occurred in college-aged students in 2006.
In the 2009-2010 outbreak, the first patient was believed to be an 11-year-old student staying in an area of the United Kingdom experiencing a mumps outbreak at the time. He returned to the United States and attended an Orthodox Jewish camp in Sullivan County, N.Y., also attended by about 400 other boys.
By the time camp ended, 25 people -- 22 campers and three adults -- had developed mumps. As the campers returned home, mumps spread within the Orthodox Jewish communities in Brooklyn and Rockland County, N.Y. From there, it spread to other Orthodox communities in Ocean County, N.J., and Orange County, N.Y.
About 71 percent of the 3,500-plus cases that eventually occurred were in males, many of them teenagers. The vaccination rates in Orthodox Jewish people were high. Of those infected, 89 percent had received the recommended two doses of the mumps vaccine, while 8 percent had received at least one dose.
All rights reserved