More than 1,500 people in the New York area, mostly Orthodox Jewish boys and young men in Brooklyn, have contracted mumps in the worst outbreak in the United States since 2006, city and federal health officials said Thursday.
The outbreak originated at an all-boys religious camp in Sullivan County in June and has spread through the tightly knit Orthodox Jewish communities in Williamsburg, Crown Heights and Borough Park, city officials said. Only 3 percent of the cases in the outbreak have been reported outside Orthodox communities, health officials said.
There have also been cases in Orange and Rockland Counties, in Ocean County and surrounding areas in New Jersey and in Quebec, health officials said.
Most of those infected are boys from 7 to 18 years old, according to a federal Centers for Disease Control and Prevention report released Thursday.
The outbreak appears to be spreading through Orthodox Jewish schools for boys, where students may spend as many as 14 hours a day together, often in large study halls and face to face with a study partner, according to the federal report.
It seems to have remained within the relatively insular Orthodox community, and the large size of Orthodox families may have made transmission easier, according to the report.
Most of the young men who were infected had been vaccinated for measles, mumps and rubella, but the mumps portion of the vaccine is less effective than the other parts, the federal report said.
“This is a well-vaccinated community,” Dr. Jane R. Zucker, the city’s assistant health commissioner for immunization, said Thursday. “If it wasn’t as well vaccinated, we would be seeing many, many more cases.”
Mumps, which is spread through infected saliva, can have potentially serious complications, including hearing loss, viral meningitis and, for men, sterility.
The city’s Department of Health and Mental Hygiene is so concerned that it is setting up vaccination programs for people age 10 or older among Orthodox Jews in Brooklyn who have never been vaccinated, or who are not sure whether they have been vaccinated. Vaccinations will be offered from 2 to 10 p.m. on Wednesday at 575 Bedford Avenue in Williamsburg and on Thursday at First Congregation Anshe Sfard at 4502 14th Avenue in Borough Park.
Other locations for free and low-cost vaccines may be found by calling 311, city officials said.
The outbreak has been traced to an 11-year-old boy who returned in June from a trip to Britain, where there had been an epidemic of mumps, and then attended the summer camp in Sullivan County.