Google is sharing its treasure trove of data about runny noses and fevers to help health researchers learn more about covid-19, the disease caused by the coronavirus. The data set could even help them predict future hot spots for the disease, or learn more about what long-term effects it has. The information goes back three years and includes up to 400 symptoms and conditions, not just those known to be associated with covid-19. It will have information on searches for things such as stress and diabetes so experts can learn more about secondary health impacts.