Typhoid-MaryThere is a great article in of all places the Wall Street Journal on how 20% of the population spread most of the illness. Ah yes, the 80/20 rule applies to disease transmission too!

Turns out that this phenomenon has been observed in numerous outbreaks including during the global SARS outbreak in 2002 and 2003 and all the way back to Typhoid Mary! By the way, that was a REAL person, a cook who lived in New York – she infected dozens of people with typhoid fever in the early 1900s without falling ill herself.

Scientists are trying to figure out why some people spread disease more than others. There are many things at play including conditions, circumstances and environments such as a crowded day-care center, and some pathogens are just more virulent than others. There is also reason to believe that the body’s immune system may play a role—not just to protect against infection but also to spread more of the pathogens to others. Kind of like “sharing the wealth” so to speak!

It is also an issue of behavior and your immune system. Which is the bigger contributor is still unknown.

What is the definition of a superspreader? There isn’t clear agreement on this one. Some experts differentiate between supershedders (individuals who emit greater quantities of viruses or bacteria) and superspreaders (those who have more points of contact with others). Scientists also aren’t clear whether being a superspreader makes it more likely the person will be asymptomatic of the disease, like Typhoid Mary.

Some scientists postulate that it is part of the virus’s survival strategy. Maybe they have even learned how to tweak a person’s immune system so that is become more effective at spreading the disease and therefore guaranteeing its survival in perpetuity.

Something to think about in the current flu season that has been forecast to be “a bad one.”