An Epidemic of FearHow Panicked Parents Skipping Shots Endangers Us AllAll Related Stories »New York City’s health department today confirmed a mumps outbreak in Brooklyn. The disease spread among children attending a summer camp in upstate New York and has affected at least 57 people ages 1 to 42, with the majority ranging in age from 10 to 15 years.
The vast majority of kindergarteners in New York — 98.5 percent -- are vaccinated against mumps. But this outbreak wasn’t limited to children who skipped their shots. Instead, three-quarters of affected people had been vaccinated. The remaining 25 percent either missed their second dose of mumps vaccine, or their vaccination status was unknown. People typically get vaccinated against mumps with the MMR (measles, mumps, and rubella) shot, which is given in two dosesat the ages of 12 months and 4 to 6 years. But the vaccine isn’t 100 percent effective. After one of the two recommended doses, the CDC found, the MMR was found to prevent mumps 80 percent of the time; two doses carry a 90 percent efficacy rate.
Travis Porco, an epidemiologist at the University of California, San Francisco, estimates that when 75 percent of a population is vaccinated against mumps, 50 percent of the unvaccinated group will catch the disease. That's in a closed community -- it's a theoretical example where no one leaves or enters a population or, say, goes to summer camp.
Caused by a virus, mumps is about as contagious as influenza, though it has a much longer incubation period -- around 17 days. And it's around for a long time -- people with mumps can transmitthe disease 7 days before symptoms appear until 8 days after symptoms subside. Because of the disease's transmissibility, the CDC recommends that people with mumps remain isolated for 5 days after the disease's onset.
In 2006 thousands of people in the Midwest were sickened by mumps; that outbreak, which began at an Iowa college, was considered the worst in 20 years.
