I had COVID-19 in a very light form and I know personally lots of others that had the disease. Here in Bergamo we soon realized that most of those infected suffered from anosmia (loss of smell) and/or ageusia (loss of taste) after the fever starts and lasting around 10 days.

After it happened to me I couldn't taste or smell anything, coffee had no taste, even the trash had no smell, so I jumped straight to DDG to search for those really strange symptoms. Then I thought that such an odd symptom could be used to track where the disease is expanding.

Here you can see how those search terms are outliers right now:

IT - https://trends.google.com/trends/explore?date=today%205-y&geo=IT&q=perdita%20gusto%20olfatto

EN - https://trends.google.com/trends/explore?date=today%205-y&geo=US&q=taste%20smell%20loss

Here the data of the last 30 days:

IT - https://trends.google.com/trends/explore?date=today%201-m&geo=IT&q=perdita%20gusto%20olfatto

EN - https://trends.google.com/trends/explore?date=today%201-m&geo=US&q=taste%20smell%20loss

The Italian data fits quite well with the reported incidence and it also looks quite good for the US data.

My question is: do we use that kind of data to track COVID-19 or other diseases with very specific symptoms? What's your take on this subject? Should we invest more? Privacy concerns?

Thanks for reading!