Latest on Midwest mumps epidemic

We haven't written here yet about the mumps outbreak affecting Iowa and neighboring states in the Midwest, but stories in today's Washington Post and New York Times address the role of the mumps vaccine in the epidemic and also provide good overviews for those who haven't been following the story over the past several weeks. On the vaccine, from the Times...

"(CDC Director Dr. Julie) Gerberding said the disease had spread quickly because of the dense concentration of students in affected cities and because the vaccine is not perfect. It has about an 80 percent efficacy rate for people who have been inoculated with one dose, and a rate of about 90 percent for people who have received the recommended two doses.

'We have absolutely no information to suggest that there's a problem with the vaccine,' Dr. Gerberding said. 'What's going on here is basically a number of people who haven't received both doses, coupled together with people who have received the vaccine but are susceptible anyway, living in crowded conditions like college dormitories or mixing up with other students at spring break or during holidays, and setting up a cascade of transmission that's going to take a while to curtail.'"

The vaccine in question is Merck's M-M-R II, the only licensed mumps vaccine available in the United States. The stories report that CDC will be shipping 25,000 doses of the vaccine from its stockpile to affected areas and Merck will donate another 25,000.

For mumps, there are no specific risk behaviors that increase the likelihood of contracting it (other than not following standard hygiene recommendations -- although people should wash their hands, etc., for many more health reasons than the very slim chance of coming down with mumps). However, the quotes from the general public in both stories reflect near-amazement that it's even possible to get mumps in 2006. While a testament to the effectiveness of decades of vaccination, these views underscore the challenge of stressing the continued necessity of high vaccination rates and the importance of reminding the public that no vaccine guarantees 100% protection against an infection. This second point becomes particularly important when vaccines provide partial protection, as is the case with HPV (which targets viral strains accounting for only 70% of cervical cancers).