Infectious Disease Prevention and Control CASE STUDY
Mumps and hockey go together like . . . a stick and a spit?
In late 2014, the US National Hockey League (NHL) faced a mystery: Why had 18 (and counting)
players come down with the mumps in the same 8-week period between October 17 and December 17?
The NHL has had a history of difficulties with stopping the spread of MRSA among players—but adding
mumps into the mix caught everyone involved by surprise. The surprise was big enough, in fact, to lead
to two lawsuits (at the time of this writing) against Merck, the pharmaceutical company that won the
right to be the sole provider of the vaccine in the United States. The company is being accused of hiding
or misrepresenting facts about how well the MMR (measles, mumps, and rubella) vaccine offers
protection against mumps.
The outbreak in the NHL led to proactive moves in other sports organizations—in particular, the
National Football League (NFL) and the National Basketball Association (NBA), especially in cities when
NHL and NBA clubs were sharing the same arena or, in the case of some teams (e.g., the New York
Knicks and New York Rangers), even the same practice facility.
Mumps is a viral infection spread mainly through saliva (by coughing, sneezing—or spitting,
something that occurs quite a lot in hockey!). After the vaccine was developed in the 1960s, mumps
became a fairly rare phenomenon (fewer than 1000 cases a year). But the past decade has seen a
resurgence, partly because many patients fail to get boosters on time, while at the same time immunity
tends to fail more than 10% of the time, even among those patients who do get all their boosters on
time. Finally, patients are contagious before symptoms show up.
So, besides some lawsuits, what has been the upshot within multiple sports leagues?
Although cases are still occurring at the time of this writing, sports leagues have called on the
Centers for Disease Control and Prevention (CDC) and other medical experts to guide them in
establishing standardized preventive measures (including the CDC’s revisiting the standards for booster
shots) and educational strategies for both players and staff on how communicable diseases are spread.
Howard J. Mumps fosters cautious approach. ESPN NHL. December 23, 2014. Accessed
January 1, 2015.
Mohamadi A. How did the NFL have a mumps outbreak? SBNation. December 5, 2014. Accessed January 1,
1. How does the agent–host–environment triangle play out here? How would you describe mumps
2. Although mumps spreads dramatically—and some said “mysteriously”—through the NHL, not
everyone was infected. What are three factors that determine who is infected and who is not?
3. Given what this story reveals about the nature of mumps’ contagious state, were players capable of
passing on the infection during the incubation period, the communicable period, or both