‘I see something terrible happening now’: Exponential COVID-19 growth worries experts

MADISON, Wis. – As COVID-19 cases, hospitalizations and deaths surge, experts see no sign of the increases slowing down unless there are some major changes.

“It took about seven and a half months or so get to the first 100,000 cases in Wisconsin,” said Ajay Sethi, assistant professor in the Department of Population Health Sciences at the University of Wisconsin-Madison. “It took about 36 days only to get the next 100,000 cases. We’re on track to getting the next 100,000 cases 20 days later.”

To put that in perspective, the 300,000 total people who have tested positive for COVID-19 in Wisconsin would fill Camp Randall Stadium more than three times over.

“A lot of cases have recovered,” Sethi said. “The 2,500 deaths, there’s no going back.”

That’s more than an average section at the stadium gone.

As daily case increases in the state regularly hit the 7,000 mark, the exponential growth in the coronavirus is concerning for UW-Madison experts like Sethi.

“I see something terrible happening right now,” Sethi said. “Right now the peak is so much larger than we have ever seen.”

News 3 Now Daily Cases Graph

Daily new COVID-19 cases in Wisconsin as tracked by News 3 Now. Note: Oct. 19 shows multiple days of data because of a weekend system upgrade.

Sethi works to model and predict potential COVID-19 growth to help UW Health prepare. Professor Oguzhan Alagoz, in the School of Engineering and School of Medicine and Public Health, is doing the same type of work.

“You are basically doubling, tripling, quadrupling the number of people transmitting the disease as a result of exponential growth, which can lead to terrible outcomes in such a short time,” Alagoz said. “This is one of the most dangerous times for our pandemic.”

He is keeping a close eye on hospitalizations, a solid indicator of the pandemic’s impacts.

“Look at all of Wisconsin. We were at 342 (hospitalizations) on Sept. 18 and now we have (more than) 2,000 hospitalizations on Nov. 10,” Alagoz said, adding that hospitalizations in south central Wisconsin have tripled in less than a month based on Wisconsin Hospital Association data. Rather than outbreaks localized to bigger cities or isolated facilities like in the spring, the virus is everywhere. “We have community spread completely out of control.”

“It’s in every age group. It’s across the entire state, so it’s just that much worse,” Sethi said. “If I think back to the earlier part when we were modeling, I don’t know if we would have ever thought it would get this bad.”

“We don’t have a good intuition about these kinds of numbers,” said John Yin, a UW-Madison professor of chemical and biological engineering, referring to exponential growth.

He explained how quickly that type of increase can get out of control using a metaphor with pennies. With linear growth, one would receive one penny each day, ending up with 28 cents after 28 days. With exponential growth, one would start with one penny and it would double every day, ending up with more than $1.3 million dollars after 28 days.

“It’s hard for the human brain to comprehend that,” Yinn said. “I had to work it out with my calculator.”

“Unless we make some major changes or a vaccine starts soon, we won’t be able to turn the tide,” Alagoz said. “That’s where I’m really worried.”

Each professor emphasized that stopping the spread is still in our hands, but it will take more people doing their part.

“It’s pretty clear the counter-intuitive things like fast or explosive growth can be countered by things like distancing or mask-wearing,” Yinn said.

Even with the abundance of numbers, Sethi said the most important thing we can do is give the pandemic a face.

“You don’t need a fancy model to know how bad things are,” Sethi said. “Any spread of COVID over Thanksgiving is inevitably going to cause somebody to miss Christmas.”

“If we are careful, we can change the trajectory of COVID-19,” Alagoz said. “If not, we won’t have any chance. It’s just going to get worse and worse.”