If 100 People Go to a Party in Fresno County, It’s 99% Someone Has COVID-19

Georgia Tech researchers have taken the guessing game out of the COVID-19 equation with a new interactive map.

The online tool calculates the county-level risk of attending an event and crossing paths with someone who has the coronavirus. Previously, only state-level data was shown.

The college says the dashboard accounts for widespread gaps in U.S. testing for the coronavirus, which can silently spread through individuals who display mild or no symptoms of illness.

The website is updated daily and incorporates data from The New York Times case count and Covidtracking.com dashboard (a resource led by journalist Alexis Madrigal of The Atlantic).

The latest figures from the Fresno County Department of Public Health show there have been 15,550 COVID-19 cases since the beginning of the pandemic. Of those, 9,907 are active.

Fresno County

In Fresno County, the interactive map indicates there’s a 99% chance of at least one COVID-19 positive individual anytime 100 or more people gather.

“Precisely because of under-testing and the risk of exposure and infection, these risk calculations provide further support for the ongoing need for social distancing and protective measures. Such precautions are still needed even in small events, given the large number of circulating cases,” states the dashboard’s website.

Access the interactive map here, and you can choose the group size you’d like to view by sliding the cursor at the bottom left of the page either left or right to decrease or increase the size.

The interactive map embedded below represents COVID-19 risk in a group of 100 people in each of the counties across the country. Hover your cursor over each county to see the possible risk for each.

99% Chance in Other Central Valley Counties

Just like in Fresno, there’s a 99% chance at least one COVID-19 positive individual will be present in a group of 100 in Merced, Madera, Kings, and Tulare counties.

“The COVID-19 Event Risk Assessment Planning Tool takes the number of cases reported in the past 14 days in each county, and multiplies these by an under-testing factor to estimate the number of circulating cases in a particular county,” says Joshua Weitz, a professor in the School of Biological Sciences and founding director of Georgia Tech’s Ph.D. in Quantitative Biosciences program.

Mariposa County Safest in Central California

Mariposa County stands out from the rest of its Central Valley counterparts.

In a group of 100 people, the interactive map shows there is a 65% chance of at least one COVID-19 positive person.

“The issue of understanding risks associated with gatherings is even more relevant as many kinds of businesses, including sports and universities, are considering how to re-open safely,” Weitz said.