The questions around the National Hockey League mumps outbreak that finally found its way to the Penguins this past weekend start with the obvious: Didn't we eradicate the mumps?
The short answer: Well, we almost did.
Once a common disease with painful and sometimes catastrophic results (sterility in men and miscarriages in pregnant women) mumps is a virus spread through saliva contact from person to person, from something as innocuous as touching the same counter surface as someone with the disease or as obvious as being near someone who sneezes.
But after the creation of the vaccine for mumps in 1967, the federal Centers for Disease Control and Prevention recommendation in 1977 that it be a regular vaccine for toddlers, and the recommendation in 1990 that a second dose of the vaccine be given to children about four years after the first, the number of cases dropped by about 98 percent.
But pockets of resistance to the eradication of the disease have persisted from several different quarters.
There are those who have resisted vaccinating their children, despite the proven success of the mumps vaccine, because of a variety of fears; there are about 10 percent of people who have been vaccinated whose bodies simply don't respond, so-called "nonresponders" who are still susceptible; and there is some belief the effectiveness of vaccination may wane over time, requiring adults to get an additional booster shot.
There also appear to be people apparently along the lines of Penguins star Sidney Crosby who were vaccinated recently and appeared to respond well to the vaccination, but still contracted the disease.
"As physicians, we were caught on our heels by this," said Matt McCarthy, an infectious disease physician for Weill Cornell Medical Center in New York City. "Why is Sidney Crosby - a young, healthy guy with a good response to the vaccine - getting this disease? There's something that's not adding up."
Prior to becoming infected sometime in the past three weeks, presumably from an opponent on one of the other four teams with the infection, Crosby had a booster shot in February before he left for the Olympic Games in Russia.
Probably as a result, his antibody count - which would show if his body could fight the disease off - was high enough when the Penguins tested him and the rest of the team Dec. 3 that they didn't think he was even susceptible. Others on the team - including Beau Bennett, who was confirmed Tuesday to also have the mumps - and staff did have low antibody counts, though, and 19 of them were given booster shots of the vaccine Dec. 6.
So what is happening that is leading to this outbreak?
Research following a 2006 outbreak of mumps in the Midwest, primarily on college campuses, found antibodies were higher in those with a more recent vaccine dose, and there was no set amount of antibodies in people that appeared to be the safe level that definitively prevented the person from contracting the disease.
"That's the problem," said Jennifer Preiss, a family physician in Pittsburgh who works with Allegheny Health Network. "No one knows at what level they're immune."
Preiss said in her 24 years of practice she has had three patients with the disease, which is why it concerns her that young, healthy men are catching it now.
Some researchers have questioned if the 2006 outbreak, and others during the last three decades, could be the result of the United States' decision in 1992 to switch the vaccine of choice from one strain to another, in an effort to be more effective.