Tool helps track COVID-19 superspreader events

A newly developed interactive map documents COVID-19 ‘superspreader events’ across the world, including about a dozen in Minnesota.

The tool is part of a ‘superspreading database‘ created by a team from the London School of Hygiene and Tropical Medicine.

If you hover over each bubble on the map, you can see information about individual outbreaks, including where and when it happened, how many people were infected and if the event was indoors or outdoors. The creators note that not every known superspreader event is on the map but it is being continually updated.

The database also analyzes the events based on setting. Currently, prisons account for 27% of worldwide superspreader events, nursing homes account for almost 17%, meat processing plants account for more than 10% and religious gatherings, including weddings and funerals, account for almost 8%.

"All it takes is for one person at that event to be infectious and, more often than not, that person will not have symptoms, so you won’t realize they’re infectious," said Ryan Demmer, associate professor of epidemiology and the University of Minnesota’s School of Public Health.

The Centers for Disease Control and Prevention does not set a specific threshold for what constitutes a ‘superspreader,’ but notes the events are "associated with both explosive growth early in an outbreak and sustained transmission in later stages."

5 EYEWITNESS NEWS previously reported on clusters of cases at the JBS Pork Plant in Worthington and a Lyon County wedding, west of the metro, which led to 75 people being infected.

The database also shows other superspreader events across the country that happened at funerals, bars and day cares.

Demmer said one of the challenges with superspreaders is they are particularly difficult to predict with COVID-19.

"People are usually most infectious in the one to two days before they develop symptoms, so even people who are trying to be really careful and they wouldn’t go to an event if they had actual symptoms, the probabilities are that they’ve done most of their spreading before they ever developed symptoms and that leads to superspreading," Demmer said.

Demmer believes we will likely see an uptick in superspreader events in the coming months.

"I’m really worried about the fall, as people move indoors," Demmer said. "There’s going to be less sunlight, you have less air circulation and generally the humidity changes in a way to subtly favor transmission."

He urges people to follow guidelines regarding social distancing and mask-wearing to help minimize risk.

"It will be hard for people to go the next six months without seeing anybody, so I imagine people will gather. Even if they are being safe, keep the groups small, two people come over and meet in a large room of your home if you can," he said. "Keep at least 10 to 15 feet from each other, you can have a conversation and keep the duration short."