When Trump last visited Macon, in 2018, and after the screams and chants from his supporters subsided, he repeated a complaint from many other of his rallies: The media never gets the crowd size right.

“I really wish the fake news media would show the crowds,” Trump said from the stage inside a hangar at the Middle Georgia Regional Airport.

“You can’t duplicate, when you have 20-, 25-, 30,000 people … you can’t duplicate that sound with 500 people.”

Thousands had indeed come to see Trump stump for then-gubernatorial candidate Brian Kemp. People who weren’t in the hangar spilled over onto the runway behind the press deck.

That was 2018, but similar scenes have been playing out in places like Sanford, Florida, and Des Moines, Iowa, in the days since Trump and about 20 people close to him were diagnosed with the coronavirus.

That leads Joshua Weitz, professor of biological sciences and physics at Georgia Tech, to a piece of advice for people thinking about attending the Trump campaign rally planned again for the airport in Macon this Friday.

“Go to this event recognizing that there is an almost certain risk that someone in that crowd will have COVID-19,” Weitz said.

Weitz came to that conclusion through an online tool he and others developed called the COVID-19 Event RIsk Assessment Planning Tool. The tool uses local data to predict the likelihood of encountering someone with COVID-19 when you get together in a crowd.

Weitz said the tool draws from latest data from the Georgia Department of Public Health, and then augments that in the context of CDC guidance on how much that data undercounts the actual number of infections.

“Between five to 10 cases may actually be taking place or may actually spread for every one that’s documented,” Weitz said.

Weitz said a Georgia-specific study found the ratio was about 10 cases for every one counted by DPH.

Then the tool considers the number of people you expect to attend the event.  You can adjust it to play with different crowd sizes. For instance, take a low estimate for a Trump rally: 500 attendees on Oct. 16.

“Well, even at 500, we get an estimate of 98%,” Weitz said.

That’s a 98% probability that someone in that crowd of 500 will have COVID-19, and could spread the virus. And, Weitz said, given what we know about people who have the virus but have no symptoms, that person spreading the virus in a crowd could be you.

Calvin Palmer, head of the Macon-Bibb County GOP, is not worried about the virus. And he said 500 people at a Trump rally is lowballing it.

“That’s just not gonna happen,” Palmer said. “I mean, he’s gonna have 20,000 people out there.”

He’s guessing of course, but the Georgia Tech crowd projection tool says a crowd of 20,000 would have a better than 99% chance, essentially a 100% chance, of containing someone with COVID-19.

Palmer is dubious about this science.  He said he’s not even sure the virus wasn’t made in a lab.

“This virus, it was in a level four containment bunker. That’s where they developed this thing,” he said, hinting at a conspiracy theory debunked by Snopes.com and others.

Even though he doesn’t think there’s any real danger associated with the virus that is known to have killed more than 215,000 Americans, he said he’ll likely wear a mask at the Macon rally on Friday.

“I would probably, to keep everybody safe around me, to make sure I don’t offend anybody or make anybody feel uncomfortable,” Palmer said. “I would wear my mask.”

Georgia Tech’s Joshua Weitz said Palmer and others should take other steps.

“I mean, there are ways to do this in a safer sense,” Weitz said. “Like having it outdoors is good. If there was a required mask rule, that would be good.”

Weitz added that people should only mix with the people they came with to the rally and maintain a healthy physical distance, too.

Macon-Bibb GOP head Calvin Palmer said the Trump campaign has told him nothing about what COVID-19 safety precautions they might have at the Friday rally. Macon-Bibb County government says the same, as does the local health department, the North Central Health District.

Meanwhile, President Trump’s own White House Coronavirus Task Force advises people in Georgia to avoid large public gatherings entirely in its most recent report. 

As for the Trump Campaign, it is treating the threat to public health as real. To get a ticket, you must first agree you won’t hold President Trump liable should you get COVID-19 at his rally.