Most people won’t spread the virus widely.

At its most intrepid, the virus can spread from a single individual to dozens of others, perhaps even a hundred or more at once, proliferating through packed crowds in what is called a superspreading event.

“There’s this small percentage of people who appear to infect a lot of people,” said Dr.

Figuring out what drives coronavirus superspreading events could be key to stopping them, and expediting an end to the pandemic.

“That’s the million dollar question,” said Ayesha Mahmud, who studies infectious disease dynamics at the University of California, Berkeley.

Schiffer and his colleagues reported that coronavirus superspreading events were most likely to happen at the intersection where bad timing and poor placement collide: a person who has reached the point in their infection when they are shedding large amounts of virus, and are doing so in a setting where there are plenty of other people around to catch it.

Schiffer’s team, the riskiest window for such transmission may be extremely brief — a one- to two-day period in the week or so after a person is infected, when coronavirus levels are at their highest.

The virus can still spread outside this window, and individuals outside it should not let up on measures like mask-wearing and physical distancing, Dr.

Symptom-free spikes in virus load appear to happen very often, which “really distorts our ability to tell when somebody is contagious,” Dr.

“These processes really come together when you are not only infected, but you also don’t know you’re infected because you don’t feel crummy.” Some of these unwitting coronavirus chauffeurs, emboldened to go out in public, may end up causing a superspreading event that sends the pathogen blazing through a new population.

Schiffer said he thought the coronavirus might be more amenable to superspreading than flu viruses because it is better at persisting in contagious clouds, which can ferry pathogens over relatively long distances.

“This study adds yet another layer to how it’s different from influenza,” said Olivia Prosper, a researcher at the University of Tennessee, Knoxville who uses mathematical models to study infectious diseases but was not involved in the study.

“A superspreading event is a function of what somebody’s viral load is and if they’re in a crowded space,” he said.