Despite high vaccination rates, an outbreak of mumps occurred in July 2005 among 541 children from the United States and abroad who attended a 4- or 7-week overnight summer camp in upstate New York.
Dr. Joshua K. Schaffzin, of New York State Department of Health, Albany, and colleagues conducted a study of this outbreak.
Of the 541 children, 31 were diagnosed with mumps, for an overall attack rate of 5.7 percent.
Of the 507 children who had their immunization history available, 440, including 16 who became ill, had received two doses of the mumps vaccine, for an attack rate of 3.6 percent.