Athlete's Foot Shares the Wealth with Mumps in Locker Rooms

Everything comes to Pittsburgh after it comes to New York: cool hamburger bars, hipsters, boutique hotels, and mumps. Headlines in Pittsburgh today are detailing Penguin captain and superstar Sidney Crosby's bout with this relatively benign disease that causes characteristic salivary gland enlargement.

As a good proportion of the population has grown up during the post-mumps vaccine era--which began in 1949--there is concern about its reappearance and the risk it confers. What bears emphasis is that mumps is not one of the horseman of the apocalypse, even if it is capable of sidelining several hockey players. As I have written before, severe complications of mumps, such as meningitis, are rare, more common in adults, and recovered from uneventfully (even those who experience meningitis).

Mumps resurgences are due to waning immunity coupled with the exposure pressure inherent in closed populations such as college dormitories or hockey locker rooms. While even I probably have waning immunity to mumps, I don't have much exposure pressure and certainly am not party to "saliva spray". As such, mumps doesn't represent a significant public health threat at this time.

The diagnosis of mumps, a nationally notifiable disease, is usually based upon seeing the classic facial appearance. Confirmation is made either by looking for antibodies to the virus, growing the virus, or detecting the genetic material of the virus. Antibody tests may be hard to interpret in a previously vaccinated person who has a breakthrough infection and may be falsely negative (as seems to be the case with Crosby); other tests may prove more useful in that setting.

Another concern is the contagiousness of mumps. While it is a minor illness, it is important to try and delimit spread. Mumps is spread through direct contact with respiratory secretions and people are contagious 2 days prior and 5 days after salivary gland swelling. I can imagine a hockey player locker room being strewn with snot, spit, and other secretions--a perfect playground for mumps.

The case in Pittsburgh has caused some added concern because another Penguin being investigated for mumps visited a hospital. Since mumps is not airborne, it is not clear that a major risk of transmission existed and even if significant exposures occurred, the consequences, if any, will be minimal as vaccination uptake is high amongst the population.

Though I enjoy it when there's general interest in any infectious disease, a recalibration of threat perception is needed: we are likely in for a rough flu season and that is of much greater concern than hockey player's faces morphing into those of chipmunks.

Hockey Players with Swollen Faces: Puck, Fist, or Mumps?

Professional sports teams, because of the close contact amongst players, are always ripe for outbreaks of contagious diseases. In the recent past MRSA has been one organism associated with sports-related outbreaks (see the St. Louis Rams).  Today, the NHL is now facing an outbreak of mumps that has plagued several teams. 

Mumps is a viral disease and is generally preventable through vaccination. It is one of the "M's" in the MMR vaccination. This vaccine, like many others, is due to the genius of Maurice Hilleman--one of the true heroes of infectious disease. It is known for causing characteristic swelling of the salivary glands but can also meningitis or orchitis (inflammation of the testicles).

However, over the past several years we've seen large outbreaks of mumps occur in certain population that are somewhat dense such as amongst college students. Interestingly, these outbreaks are occurring in relatively highly vaccinated groups of individuals (vs. measles, for example). 

So why are these outbreaks occurring? When a vaccine fails I think of one of two causes: the pathogen has mutated or the immunity induced by the vaccine has fallen below a protective threshold. While the strains causing these outbreaks (G) is different than the vaccine strain (A), G strain outbreaks are halted by the A strain vaccine. So strain disparity doesn't seem to be the explanation. There has been some suggestion that a third booster dose of the vaccine can bring outbreaks to a halt supporting the waning immunity theory.

Another factor is something called "exposure pressure." Since these outbreaks are occurring in specific "closed" populations could it be that the amount of exposure an adequately vaccinated individual has to the virus in these outbreak settings overwhelms the immune system?

My hypothesis is that it is probably waning immunity coupled to exposure pressure that explains these outbreaks. Outside of outbreak settings mumps has become much less common and any natural boosting of vaccine immunity from exposure to natural cases is no longer present, allowing antibody levels to fall. Those with waning immunity are simply unable to resist the virus when faced with the exposure pressure in a closed population in which mumps is being harbored.

There are reports that some teams are moving forward with booster doses, which should stem the outbreak. But, it remains important to understand more fully why these outbreaks continue to occur and whether universal 3rd boosters should be considered for certain populations.

Mumps: Don't Call it a Comeback

In the midst of news regarding measles and pertussis, two diseases enjoying resurgences due to lack of immunity from lax vaccination attitudes (see this Pittsburgh Tribune Review article), mumps also appears to be making a comeback. In fact, however, the 2014 outbreaks at Fordham and Ohio universities are part of a trend that began in the US around 2006.

In contrast to the other vaccine preventable diseases, mumps appears to be somewhat mysterious in that it occurs in highly vaccinated populations and not in those lacking immunity. Such outbreaks didn't occur pre-2006 which leads to several questions: 

1. Has the mumps virus strain changed to a point where it is somewhat less likely to be stopped by the current vaccine's induced antibodies?
2. Do crowded conditions at college campuses somehow overwhelm immunity?
3. Are there super spreaders who shed high amounts of virus? 

Overall, though mumps is a much less virulent disease than measles and has less individual--and public health--import.