>> If enough people who suddenly found themselves without a sense of smell self-reported their condition, you might well create an early warning signal that told you where the virus was heading, and how fast.
I am skeptical. A test based on the sense of smell would have a very high amount of noise. There is no good, concrete measure of a person's sense of smell. One has to ask the person to get a "measurment" and it's very hard to know what different people would mean by "I can smell fine" or "I can't smell as well as I used to".
Maybe some people would convince themselves they have no sense of smell (like some people convince themselves they are gluten or lactose "intolerant"). Maybe some people who have a weak sense of smell anyway (because they smoke or live in places with a high level of air pollution) would tend to ignore having completely lost their smell.
In any case, it would be very hard to track real infections with such an unreliable measure.
I am skeptical. A test based on the sense of smell would have a very high amount of noise. There is no good, concrete measure of a person's sense of smell. One has to ask the person to get a "measurment" and it's very hard to know what different people would mean by "I can smell fine" or "I can't smell as well as I used to".
Maybe some people would convince themselves they have no sense of smell (like some people convince themselves they are gluten or lactose "intolerant"). Maybe some people who have a weak sense of smell anyway (because they smoke or live in places with a high level of air pollution) would tend to ignore having completely lost their smell.
In any case, it would be very hard to track real infections with such an unreliable measure.