‘Superspreaders’ Could Actually Make Covid-19 Easier to Control

At a Feb. 15 workshop for Zumba instructors in the South Korean city of Cheonan, one person infected with Covid-19 spread the disease to seven others, who then passed it on in the classes they taught, with the resulting outbreak infecting more than 100. In early March, one member of the Skagit Valley Chorale in Mount Vernon, Washington, seems to have infected as many as 52 others at choir practice. Then there’s the guy at the seafood processing plant near Accra, Ghana, who was reported this month to have infected 533 co-workers.

These “superspreading” events have become a trademark of the new coronavirus — at first impression quite a scary one. But most people who get the disease don’t pass it on to dozens of others, and many don’t pass it on to anyone at all. One new global study estimates that about 10% of those infected with Covid-19 cause 80% of the secondary transmissions; another study focused on Israel puts that share between 1% and 10%. This imbalance explains a lot about why Covid-19 has spread so unevenly and unpredictably around the world. It also, perhaps counterintuitively, appears to make the disease easier to control than it would be if superspreaders weren’t so important.