Growing evidence shows most infected people aren’t spreading the virus. But whether you become a superspreader probably depends more on circumstance than biology.
“You can think about throwing a match at kindling,” said Ben Althouse, principal research scientist at the Institute for Disease Modeling in Bellevue, Wash. “You throw one match, it may not light the kindling. You throw another match, it may not light the kindling. But then one match hits in the right spot, and all of a sudden the fire goes up.”
If Covid-19 was like the flu, you’d expect the outbreaks in different places to be mostly the same size. But [researchers] found a wide variation. The best way to explain this pattern, they found, was that 10 percent of infected people were responsible for 80 percent of new infections. Which meant that most people passed on the virus to few, if any, others. … It’s possible that some people become virus chimneys, blasting out clouds of pathogens with each breath.
Some people also have more opportunity to get sick, and to then make other people sick. A bus driver or a nursing home worker may sit at a hub in the social network, while most people are less likely to come into contact with others — especially in a lockdown.