The New York Times – They can also reveal symptoms that at first went undetected. I may have found a new one.”…To see the potential information lying in plain sight in Google data, consider searches for “I can’t smell.” There is now strong evidence that anosmia, or loss of smell, is a symptom of Covid-19, with some estimates suggesting that 30-60 percent of people with the disease experience this symptom. In the United States, in the week ending this past Saturday, searches for “I can’t smell” were highest in New York, New Jersey, Louisiana, and Michigan — four of the states with the highest prevalence of Covid-19. In fact, searches related to loss of smell during this period almost perfectly matched state-level disease prevalence rates, as the accompanying chart shows…Vasileios Lampos, a computer scientist at University College London, and other researchers have found that a bevy of symptom-related searches — loss of smell as well as fever and shortness of breath — have tracked outbreaks around the world. Because these searches correlate so strongly with disease prevalence rates in parts of the world with reasonably good testing, we can use these searches to try to find places where many positive cases are likely to have been missed…”