Though opening the economy is Texas’ “moral duty,” allowing businesses to reopen will most likely result in an increased number of coronavirus cases, according to one of the mathematicians behind San Antonio’s predictive models for the local coronavirus outbreak.

That’s the scenario that Juan Gutiérrez, chair of UTSA’s mathematics department, presented when he joined Rivard Report Senior Reporter Brendan Gibbons for a virtual question-and-answer session Wednesday. Gutiérrez led the development of one model that the City of San Antonio publishes on its COVID-19 webpage.

Under current stay-at-home orders that closed schools, restaurants, movie theaters, and malls, San Antonio would not see more than 2,000 cases, Gutiérrez said. But on Friday, businesses will be able to open at 25 percent of their capacities under Gov. Greg Abbott’s recent executive order. Even that slow reopening will likely increase the number of coronavirus cases in Bexar County, Gutiérrez said.

That increase could be small, or it could be as much as 10 times the cases Bexar County has today, he said. Mathematicians will not know how large of a spike to expect after Friday until there are at least two more “generations” of the virus, Gutiérrez explained, meaning one person infects another and then that infected individual goes on to pass coronavirus to yet another person. That should only take about two weeks, he estimated.

“At that point, we will have enough information to see what [direction] the trajectory is going in,” he said.

Gutiérrez said models projecting future case numbers of coronavirus will not be precise. Like hurricane “spaghetti models” predicting where a hurricane will hit, researchers continuously input more data to provide more updated projections of COVID-19 cases.

Juan Gutierrez, chair of the UTSA Mathematics Department Credit: Courtesy / UTSA

“None of the models is exactly right,” he said. “But the consensus of multiple approaches normally gets it right, although we might have surprises. Sometimes with hurricanes, normally we get it right, and the closer it gets to shore, the more certainty we have about the projections that are being made.”

Gutiérrez updates his local models daily. Under current stay-at-home restrictions, Gutiérrez said it appears San Antonio has passed its “peak” of active coronavirus cases. According to the San Antonio Metropolitan Health District, there were 689 active cases as of Tuesday. But the “mid-point” risk – meaning the risk of transmitting coronavirus is somewhere between opening up activities indiscriminately and following current guidelines in San Antonio – puts San Antonio’s peak in early June.

Having no social distancing or public health guidelines would push San Antonio’s case numbers into the hundreds of thousands, according to Gutiérrez’s model.

The wide disparity of projections between opening up businesses more and continuing to follow current guidelines is due to how contagious coronavirus is, Gutiérrez said. In his report updated Tuesday, Gutiérrez estimated the R0 variable falls somewhere between 5.5 and 25.4. R0 – which is spelled with a capital R and the numeral zero, and pronounced “R naught” – shows the number of infections expected to come from individuals with coronavirus. That means each person who has coronavirus would infect somewhere between 5.5 to 25.4 other individuals.

“If [this number] is less than one, it means that the disease will just disappear,” Gutiérrez said.

For context, the extremely contagious disease measles has an R0 of between 15 and 18, Gutiérrez said; an R0 between 5 and 26 is not unheard of.

But no matter what, staying under indefinite lockdown is not the answer, Gutiérrez emphasized.

“I just want to be very clear about the need, the moral duty to restart the economy,” he said. “To give our most vulnerable populations the ability to earn an income and be able to pay bills and buy food and just exist, and hopefully more than just survive.”

To keep himself healthy, Gutiérrez said he washes his hands frequently and wears a face mask whenever he goes into public spaces like grocery stores. He’s not sure how much longer people will need to adhere to social distancing recommendations of staying 6 feet apart from others or keeping their faces covered around people not in their household.

“We have to look at the data and observe,” he said. “We hope that community transmission will decrease in a few weeks or months. In this moment, we expect it to grow, as we mentioned before. Summer might bring some relief. But it’s too early to determine that summer will be indeed a game changer for this disease.”

He also reminded listeners about the 1918 Spanish flu pandemic, where a resurgence of cases killed more individuals in the second “wave” of infections.

“It’s too early to predict whether this is going to happen with this pathogen, but it’s likely,” he said. “We cannot neglect the possibility and [let it] out of our radar.”

Missed the event? You can watch a recording of it here.

Jackie Wang

Jackie Wang is the local government reporter at the San Antonio Report.