https://www.wired.com/story/everything-you-need-to-know-about-coronavirus-testing/

The state of Ohio has, as of this writing, five confirmed cases of Covid-19, the disease caused by the coronavirus SARS-CoV-2. If you ask Amy Acton, the director of the Ohio Department of Health, that’s the tip of the tip of a very dangerous iceberg. “We know now, just the fact of community spread says that at least 1 percent, at the very least 1 percent, of our population is carrying this virus in Ohio today," Acton said at a press conference on Thursday. "We have 11.7 million people." In other words, Acton was implying: 117,000 cases in Ohio alone.

How could Acton know this? Well, technically, she can’t. She was extrapolating from what little data scientists actually have about the spread of the pandemic. Officially, there have been just shy of 130,000 cases of Covid-19 on Earth, so a six-digit toll among Ohioans would be terrible, with extraordinary implications for how many cases might be out there undetected in the rest of the country.