Gatherings a ‘large driver of community spread,’ leaders urge caution

Online tool estimates risk of COVID encounter by county, crowd size

MADISON, Wis. – Dane County public health officials are urging people to double-down on safety precautions in Wisconsin, where the rate of catching the coronavirus is more than double that of the country’s.

According to Public Health Madison & Dane County Director Janel Heinrich, the COVID-19 rate for the state is 97.4 per 100,000 people. It’s 31.5 for the rest of the country. In Dane County, the rate is 61.8.

Heinrich said that trajectory will continue to rise if people don’t change their behaviors, especially as the holidays approach. She said that about 25 to 30% of those newly diagnosed with COVID-19 in Dane County had attended a gathering. About a third believe they contracted the virus from a member of their household.

“Many of those household members have attended gatherings with people from outside their household,” Heinrich said. “This is a large driver of community spread of COVID.”

COVID-19 risk assessment tool puts things in perspective

“We can’t see the virus, but it’s there,” said Clio Andris, an assistant professor at Georgia Tech’s School of City and Regional Planning and School of Interactive Computing.

A COVID-19 event risk assessment planning tool puts it on display. A collaborative project between professors at the Georgia Tech and researchers at Stanford University, it estimates the percentage of risk that at least one COVID-19 positive person is at a certain sized gathering in each county in the country.

Users of the tool can set the hypothetical crowd size in increments from 10 to 5,000.

“The reason we wanted to make this map was to help people understand the risk of attending an event given the event size and where they’re attending the event,” Andris said.

The numbers are often updating, but as of Monday evening, the tool estimated the chances that one person with COVID-19 is in attendance at a 10-person gathering in Dane County at 34%. In Dodge County, where the risk seems to be highest out of neighboring counties, that risk was estimated at 71%.

“That’s a very high number. I know Wisconsin has some of the highest numbers in the country right now,” Andris said. “You shouldn’t get together with ten people. It’s not a good idea.”

When you raise the amount of people at these hypothetical events, those numbers only go up.

In Dane County, a 15-person gathering gives you a 47% chance of running into someone with COVID. That’s 84%  in Dodge County.

Head to a gathering with 25 people in Dane County, and your risk is set at 64%. In Dodge, that number is 95%.

Dodge County does have the Dodge Correctional Institution, which accounts for hundreds of positive COVID-19 cases to make up the county’s current total of 5,840.

Most counties in southern Wisconsin hit a more-than-99% risk of someone having COVID at gatherings of 100 people.

“We do not take into account mask-wearing, how long you’re with people. We do not take into account whether you’re indoors or outdoors,” Andris said. “All we take into account is group size.

She stressed that situations in which you socialize are the most risky.

“Somebody might spend time with people and then they bring it home. The research has shown that is the most popular place,” Andris said. “The grocery store is not your big worries. It’s the dinner party that’s the worries. It’s going out to eat that’s the worries. It’s all hanging out together drinking watching the game indoors that’s the worries.”

ICYMI, from our news release a few days ago:

“People seem to make exceptions around friends and family, but this…

Posted by Public Health Madison & Dane County on Monday, November 9, 2020

Leaders and researchers hope some perspective will be enough to keep people home.

“We know what’s driving this expansion of the virus,” Mayor Satya Rhodes-Conway said. “It’s folks getting together indoors.”

“Contact tracing notes regularly mention the words birthday, football, wedding, church, party, most recently Halloween,” Heinrich said. “I’m asking you to lean in and think about how you can adapt your individual actions to help reverse the trend of rising case counts.”