The National Hockey League saw an outbreak of mumps earlier this season. Over 20 players and two officials were diagnosed with or showed signs of the disease.
Sidney Crosby of the Pittsburgh Penguins, Derick Brassard of the New York Rangers, and Corey Perry of the Anaheim Ducks are among the players that have been diagnosed within the last few months.
Mumps, which is a contagious infection that causes swelling of the salivary glands, fever and aches, is now considered a rare disease in the United States. Since the MMR vaccination became popular in the 1970s, the number of annual cases of measles, mumps and rubella has decreased exponentially. The total cases of mumps plummeted from hundreds of thousands annually to only 1,078 in 2014 (note that this statistic is cases reported as of November 29th). In 2013, these numbers were even lower, with only 438 people diagnosed with mumps. These small numbers are largely due to the MMR vaccine; although it is not 100 percent effective, it prevents the vast majority of cases of mumps, especially when the two dose series is completed.