On the other side of it, there's selection bias--most identified cases have visible and notable symptoms, some very severe. If you have a mild cough or a bit o

On the other side of it, there's selection bias--most identified cases have visible and notable symptoms, some very severe. If you have a mild cough or a bit of a cold, you might not think anything of it beyond staying home from work, but that could be COVID-19 (and we might _never_ know that it was).