Mumps is a vaccine-preventable viral illness that causes inflammation, swelling, and pain in the parotid (salivary) glands. The virus is highly contagious through the spread of infected saliva by coughing, sneezing, or sharing objects like cups and utensils. A few days of non-specific symptoms — fever, body aches, headaches, fatigue, loss of appetite — generally precede salivary gland swelling. Complications of mumps occur with some frequency and include orchitis in males (a very painful infection of the testicles), encephalitis, meningitis, and deafness. There are three essential factors that make mumps contagious despite high immunization rates among children:
— The incubation period for mumps is rather long for a virus — 2-3 weeks. That means a person can spread the virus around well before symptoms of infection appear.
— About a third of people who acquire mumps infection have no symptoms, or very mild symptoms, and escape diagnosis. These lucky people are still contagious to others.
— The MMR vaccine is very effective but is not 100% protective. The mumps component of the vaccine is 78% effective after the first dose and 88% effective after the second. Also, for some people, immunity to mumps may wane over time. And certain medical problems and treatments, like immune disorders and chemotherapy for cancer, may compromise a previously vaccinated person’s immunity.
That last point is important and highlights the fact that getting a vaccination doesn’t just protect you — it protects those around you, including family members and friends, classmates, coworkers, fellow patients and staff members in doctors’ offices, and perfect strangers.
2016 saw a huge spike in mumps cases in the U.S. with 4,258 reports to the Centers for Disease Control and Prevention in the first 11 months. By comparison, there were 229 cases reported to the CDC in 2012 and more than 1,000 cases in 2014 (involving a bunch of players in the National Hockey League). Before the U.S. mumps vaccination program began in 1967, there were 186,000 reported cases annually (and many, many more that went unreported). In fact, since immunization has become routine, there has been a 99% decrease in reported mumps cases! Still, 2016 marked the biggest jump in mumps cases since 2006, mostly among college students on campuses like Harvard, Tufts, University of Missouri, the State University of New York, and schools in Arkansas. In all, mumps was reported in 46 states and the District of Columbia in the first 11 months of 2016. By early December, there was a new outbreak among college students in Texas. In every outbreak, it seems that children and adults who are unvaccinated are the likely targets of the epidemic virus and 2016’s mumps outbreak was no different.
MMR vaccine does not protect against disease 100% of the time. (Neither do seat belts, air bags, car seats, and a whole lot of other things that mostly do a good job preventing catastrophic outcomes.) But it safely saves a lot of people, especially children, from illness, pain, and suffering. That’s a pretty good deal!