Oura’s smart rings can now tell when you’re getting sick Symptom Radar flags when you have no signs, minor signs, or major signs of respiratory illness. | Photo by Amelia Holowaty Krales / The VergeAt the height of the covid-19 pandemic, many wearable companies rushed to see if their devices could detect early signs of the disease. Now, four years later, Oura is officially launching a feature that can…