Ongoing mumps outbreaks around the United States show that the virus can occur even in vaccinated populations, though health officials stress that the mumps vaccine does prevent larger outbreaks from occurring.
Thanks to high vaccination rates in the United States, mumps has become increasingly uncommon over the last 5 years. However, 2016 has seen a higher than normal number of cases of the virus, affecting colleges and communities across the country and making this the worst year for mumps in a decade.
Mumps infections cause swelling in the salivary glands that result in puffy cheeks and swelling in the jaw, along with symptoms such as fever, headache, fatigue, muscle aches, and loss of appetite. Outbreaks of the virus are most likely to occur in situations of close and prolonged contact such as classroom and dormitory settings.
About 186,000 mumps cases were once reported each year prior to the start of the US mumps vaccination program in 1967. Today, large numbers of cases are much less common, with as many as 2,612 reported in 2010, and as few as 229 reported in 2012. However, 2016 marks a slew of mumps outbreaks across the United States. According to a recent Morbidity and Mortality Weekly Report from the Centers for Disease Control and Prevention, there have been 3,832 mumps cases so far in 2016, more than triple the 1,088 cases that had been reported in 2015. The last time the US experienced a bigger mumps outbreak was in 2006, when the country saw more than 6,500 cases
Health officials from the University of Missouri reported 128 confirmed and probable mumps cases among students, the single biggest outbreak in a recent string of outbreaks across the United States. The mumps toll at the university continues to grow following a health advisory released by the Missouri Department of Health and Senior Services in November to notify healthcare providers of the outbreak. A health alert issued by the university’s student health center noted that the majority of the cases have occurred in students with links to Greek organizations. Out of precaution, university officials cancelled a popular finals’ week late-night breakfast event and urged students to cancel or postpone other social events. School representatives reported that although all students infected in this outbreak received the required two doses of the measles, mumps, and rubella (MMR) vaccine, it does not prevent all mumps infections.
The State University of New York in New Paltz has also reported an outbreak which now includes 36 confirmed cases of mumps, including two staff members along with students on the school’s swim team. Officials from the Ulster County Health Department also reported a probable case in a student from the nearby New Paltz High School. In a set of precautionary measures aimed to minimize the spread of the outbreak, student health service members have asked that infected students who received mumps immunizations stay isolated for a recommended time period. In addition, 20 infected students who have not been immunized were sent home, per Ulster County Health Department and New York State Health Department guidelines. Health service staff are educating student residents and athletes on how to reduce risk of exposure to mumps, and the university is asking all students to provide either documentation of mumps vaccination or of religious or other exemption. Out of precaution, the SUNY New Paltz swim team has cancelled all swim competitions against other university teams for the rest of the semester.
A mumps outbreak outside of a university setting has also emerged in Washington’s King County, where the number of confirmed and probable cases in the town of Auburn has reached 31, with another 10 cases under investigation. Local officials said that 20 of those infected are children between the ages of 5 and 17 years of age and all were vaccinated for the virus.
Additionally, new mumps cases in the Dallas-area Cleburne Independent School District and Keene Independent School District, along with confirmed cases in four Dallas County adults, prompted a health advisory from Texas state health officials.
The Centers for Disease Control and Prevention (CDC) notes that two doses of the MMR vaccine have an 88% effectiveness rate in preventing the infection, while one dose is about 78% effective. Under the CDC-recommended course for the MMR vaccine, children should receive their first shot at 12 through 15 months of age, and their second shot at four through six years of age. Individuals with mumps infections can spread the virus through coughing, sneezing, or talking, by sharing items such as cups and eating utensils, and by touching objects or surfaces with unwashed hands. Typically, symptoms appear within 16 to 18 days of infection, though they can appear within 12 to 25 days. Although the vaccine is not 100% effective at preventing mumps infections, health officials say it is still the best way to prevent infection with the virus and stops much larger outbreaks from occurring.
You can keep up-to-date on this and other outbreaks through Contagion’s Outbreak Monitor.