Enlarge Image Screenshot of Kinsa map by Amanda Kooser/CNET

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COVID-19, the disease caused by the novel coronavirus responsible for a global pandemic, has some telltale symptoms, including fever. A network of smart thermometers made by health tech company Kinsa has produced an eye-opening view of how fevers are spreading across the US.

Kinsa has made its US Health Weather Map available to the public. The company's smart thermometers work with an app that sends anonymized data to Kinsa. The aggregated data has previously been used to track the spread of the seasonal flu, but it may also help health professionals and the public keep an eye on COVID-19 hot spots.

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Enlarge Image Kinsa

The map measures observed illness levels, but Kinsa is clear it's not directly measuring COVID-19 infections. However, the company said it has seen "a very strong correlation between cumulative atypical illness incidence and positive COVID-19 tests" at the state level.

"We hope this map serves as a guidepost for public health first-responders," Kinsa spokerperson Nita Nehru said in an email. "If we see something unusual, such as an unexpectedly high level of illness, investigation needs to be done, and it needs to be done now so that we have the best shot at society's limited resources being put to their best use."

Kinsa has sold over 1 million smart thermometers and is continuing to distribute them at a rate of 10,000 per day. "Our network mirrors population density quite well -- metro areas have higher penetration than rural areas, for example," Nehru said.

Infectious-disease-dynamics specialist Benjamin Dalziel, an assistant professor in the College of Science at Oregon State University, collaborated with Kinsa to create the map. Dalziel has been working on analyzing flu transmission to forecast the spread of illness. That skill set combined with Kinsa's data helped to bring the map into being.

The map is updated nightly and shows the difference in influenza-like illness activity compared with what would normally be expected at this time of year. "We don't know that it's COVID-19, we just know that its anomalous levels of influenza-like illness. It could be a resurgence of flu," Dalziel said. However, early data on the spread of COVID-19 cases seems to be tracking well with Kinsa's statistics.

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Dalziel likens the COVID-19 pandemic to an invisible forest fire, and hopes the map may make it more visible for the general public. "I think it may be helpful for folks to maintain motivation to do the things that we know can make a difference in flattening the curve," he said.

Dalziel and Kinsa are inviting scientists and health professionals to scrutinize the map and its data, and to provide feedback. "It was a real leap of faith to put it out this early," Dalziel said.

If the map ends up matching the spread of the coronavirus, it could end up acting as an early warning system. Now more than ever, health workers need all the information they can get.

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