With its high-speed play, razor-sharp skate blades and frequent punch-ups between players, hockey has long been recognised as one of the world’s more dangerous sports. But now its players face a new, more insidious threat: mumps.



At least 15 NHL players have come down with the disease, which started among the Anaheim Ducks and spread to the Minnesota Wild, New Jersey Devils, Pittsburgh Penguins and New York Rangers.

Mumps, the symptoms of which include painful swelling of glands in the throat and groin, is caused by a virus and spread by airborne droplets of saliva. In extreme cases, it can cause infertility.

The NHL outbreak is not the first this year. In February, the virus emerged at Fordham University’s Rose Hill campus in the Bronx; in March, another, at Ohio State University, infected more than 100 students.

Part of the reason current NHL players are at risk is because they fall into something of an immunity gap. Before 1971, when the mumps vaccine became widely recommended by the CDC in the US, mumps was widespread – so those born before that are probably immune from having had the disease as children.

But it wasn’t until 1996 that it became clear mumps required a second vaccine due to immunity fading over time. That means those born between 1980 and 1992 are most at risk.

If children are protected by immunisation, then there is no way for the disease to return into the general population, even if the at-risk group’s immunity begins to slip.

“The way diseases like this make a comeback require that [they] be present in the community, meaning children are not being vaccinated by their parents,” said Bruce Polsky, chairman of the department of medicine at Mount Sinai St Luke’s and Roosevelt, and a professor of medicine and pathology.

An anti-vaccine movement has led some parents to decide not to give their children the MMR vaccine. This, according to Polsky, breaks up the “herd immunity”.

“If you continue to vaccinate the most vulnerable – children – you interrupt the reservoir of the disease in the population,” he told the Guardian. “When that doesn’t occur, the adults who have immunity which often wanes in time – they become susceptible.”

“When children are not vaccinated according to schedule,” he said, “that allows diseases like mumps to re-emerge.”

This is probably compounded by the close proximity and exertion of sport, especially the hockey rink and locker room. “If you introduce a virus into a team environment, you’ve got transmission of illness before people maybe recognise they’ve got it,” said Shelley Deeks, an associate professor of immunology at the University of Toronto. “You can see how: sharing water bottles, sharing the environment, pretty intense close contact.”

Polsky put forward a more visceral theory of why NHL players might have gotten the disease. “Mumps is a virus that is secreted in very large quantities in salivary juice,” he said. “If you watch a hockey game, you can see the saliva spray sometimes.”