Why are the Brandon Wheat Kings getting the mumps?

The Brandon Wheat Kings hockey team has announced that it’s currently dealing with an outbreak of the mumps, with a reported two cases confirmed and at least three others in question.

The Western Hockey League team put out the news yesterday that members of the team had been infected with mumps, with the Brandon Sun later reporting that two players had been confirmed with the disease and three others as possibly infected. The Wheat Kings stated that the team and the WHL are in contact with Manitoba Public Health and are taking steps to contain the outbreak.

The mumps is an infectious disease that causes fever, swelling of the salivary glands in the face and neck and, in rare cases, a temporary form of meningitis and temporary hearing loss. Ten per cent of mumps infections lead to meningitis, which is usually symptomatic as fever, headache, vomiting and neck stiffness. Most people with cases of the mumps recover in a period of a few weeks.

The mumps used to be a very common illness among children (up to 90 per cent infection rates), but since the introduction of a mumps vaccine in 1969, the disease has been severely restricted, with only a small number of cases occurring across Canada each year. There were fewer than 400 cases a year during the early 1990s, for instance, and an all-time low of 32 reported cases in 2004.

Yet, outbreaks do occur, usually due to close contact environments like university dorms, public schools and, in this case, sports teams. Two years ago, the mumps went through the NHL, infecting players on a number of teams, including Sidney Crosby of the Pittsburgh Penguins.

The case of Crosby is indicative of the difficulty in fully protecting a population from diseases like the mumps. Crosby had been immunized twice against the mumps, but vaccines do not provide 100 per cent immunity. In Canada, a one dose vaccine was employed between 1970 and 1992, after which a second dose was added to the regimen. One vaccination is thought to be between 70 to 80 per cent effective in protection against catching the mumps, while a second dose boosts that number up to 90 per cent.

In North America, mumps outbreaks have occurred in a variety of situations with different age groups. In 1998, a school-based outbreak in Montreal infected 37 children of an average age of ten years, while a larger outbreak in the U.S. midwest in 2006 infected 6,500 young adults between 18 and 24 years of age. Most often, outbreaks occur even in situations where the population has been sufficiently vaccinated — most of those people in the 2006 U.S. outbreak had received two doses of mumps vaccine, for example.

Yet, there are cases where low vaccination rates have played a role in the virus’ spread. A 2002 outbreak in northern Alberta, for example, involved an under-vaccinated community and infected 193 people.

Overall, Canada’s immunization rates are good, but they could be better, says Dr. Noni MacDonald of Immunize Canada, who pointed out that Canada is behind both the U.S. and the United Kingdom in its immunization rates. “We’re still having pertussis (whooping cough) outbreaks. We’re still having measles outbreaks, and this shouldn’t be happening,” MacDonald said to the Ottawa Citizen. For full protection and strong limitation of the spread of infection, known as herd immunity, immunization rates need to be above 95 per cent.

“We’re nowhere near that,” said MacDonald.