Clumps of mumps

Since last summer, an outbreak of mumps has been spreading in New York and New Jersey, mostly among Orthodox Jews. The AP has the story:

The 7-month-old outbreak began last summer at a boys camp in the Catskills. The campers were from Orthodox Jewish families, and cases multiplied when they returned to their close-knit communities in and around New York City.

The story is based on a CDC report that says the communities in which the virus is spreading vaccinate at about the same rate as the general population. Cultural factors may be aiding the spread of the mumps:

[M]uch of the current outbreak is occurring in congregate settings, where prolonged, close contact among persons might be facilitating transmission. Within the affected religious community, cases have occurred predominantly among school-aged boys, who attend separate schools from girls. The higher rate among boys might be a result of the additional hours that boys in this community spend in school compared with girls, including long periods in large study halls, often face-to-face with a study partner.