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ASU model looks at new COVID-19 curve, shows policy options

Posted at 5:53 PM, May 18, 2020
and last updated 2020-05-18 23:36:28-04

New research from Arizona State University professors advises what to watch for as businesses reopen and what to do if coronavirus cases spike.

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The research group, which also sends modeling to the Arizona Department of Health Services, decided to independently release its results after their work was controversially "paused" by state officials earlier this month.

The team, led by Prof. Timothy Lant of ASU's Biodesign Institute, also created an interactive website showing coronavirus cases across Arizona. Users can compare statewide data to the nation, as well as look at transmission rates county-by-county.

The ASU white paper, COVID-19 Healthcare Demand Projections: Arizona, calculates the state's true coronavirus exposure rate as four to six times the number of confirmed cases. This takes into account asymptomatic cases, false negative results, and under-testing. The researchers estimate as many as 40 percent of people exposed to coronavirus are asymptomatic and could unknowingly spread the disease.

"This model is very specifically designed to help with the current situation in Arizona," Lant said. The model looks at several scenarios for what could happen now that businesses and public places are reopening.

According to the ASU model, interactions between people will increase now that the stay-at-home order has been lifted. The researchers try to calculate the average number of infectious people that susceptible individuals contact and the probability of transmission from those contacts.

"If you’re hanging out in a public place where you don’t know the people around you, and then you get it," Biodesign Institute Executive Director Joshua LaBaer explained. "There’s no way to let those people know that they got it and that they were exposed, so the anonymous stuff is the stuff that’s the scariest."

According to the model, if virus transmission increases 30 percent, hospitals could get overwhelmed with new cases as early as July. Arizonans can help lower the transmission rates by limiting visits to public places, wearing masks, maintaining a six-foot distance, and frequently washing hands.

The researchers say looking closely at new case and hospital data between two and four weeks from now should show the new transmission trend. If the impact is significant, the researchers would recommend swift action to mitigate the peak.

"That means there’s a lot of fuel for the fire that's still left - a lot of people who could still get this virus " explained LaBaer. "What’s keeping it at bay at all is people practicing safe social distancing, wearing masks when they can, avoiding a lot of contact."

Options include a "reactive shutdown" to close businesses again.

"Public communication is important, in addition to regulations, and how it’s all enforced is also important," Lant said.