CU Professor: Coronavirus Super-Spreader Events Share Common Pattern

DENVER (CBS4)- You may have seen the photos now showing the seating charts at the Rose Garden ceremony where Amy Coney Barrett was introduced as the President's nominee for the Supreme Court. The number of people infected with COVID-19 who attended that event has been rising daily.

"There's a lot of pictures of the outdoor event but it is also part of the day were the standing meetings indoors," notes University of Colorado professor of Chemistry and Environmental Sciences Jose Jimenez. "There were a couple of rooms in the White House that had a lot of meetings, with a lot of talking in those rooms."

Jimenez has studied a super-spreader event that occurred in the early days of the pandemic on March 17 in Skagit County, Washington. One infected person ended up infecting 52 people over 2½ hours of a choir rehearsal.

"We believe that basically all the super-spreading events that have been studied share a common pattern. You basically have a lot of people that are sharing the air… (They are) sharing the area for a long time with some kind of activity that favors the virus going into the air like singing or talking or something like that."

In Colorado, Gov. Jared Polis has referred to super-spreader events when he has talked about improper gatherings in Boulder. They are defined by large outbreaks attributed to a single time and location. Contact tracing can help identify them, but it depends on whether people are up front about where they've been.

"We do the best we can to build relationships with people with the time that we have available," said Christine Billings, who heads Jefferson County's Office of Pandemic Response. "Of course we come across those that aren't and that's OK. We just hope that they pick up the phone and they answer the call and they give us the information that helps us control the disease in the community."

In Jefferson County, health officials allow events with larger crowds, but those hosting them must be collecting information.

"So we are looking to make sure that they are collecting the names and the contact information of those who were attending so that should there be some sort of exposure, our contact tracers and case investigators are able to tie back that event with their attendance say, 'Hey you were potentially exposed,'" said Billings.

It's not likely that there are super-spreader people, but possible said Jimenez, who said it's not entirely clear. There are people in the midst of their most infectious period of COVID-19.

"So it's a window of about three days… about two days before the symptoms start and the day of the symptoms start or the day after that. That's kind of the window of maximum of infectivity."

Given that information, it may be that the Rose Garden ceremony included someone with no inkling of the disease. But with few protections at the White House, the idea that infection could spread widely seems not far-fetched.

"You may do the same thing many times and not get infected and then do it one more time and then have the bad luck that someone very infectious is there and then other people get the disease," said Jimenez.