It may have been spreading longer than since early Nov. 2019. Back in 2015 winter, husband and I both got a very strange flu. We were sick for about a month and it really affected our lungs, which hurt. Not bad enough to go to hospital but we were in very good health at the time. We wondered if it was pneumonia. When covid came out we wondered if that's what we got in 2015. When covid first came out it was called coronavirus. My husband is virologist/immunologist with 55 yrs research behind him who worked for Public Health in PA. He said coronavirus is one form of the common cold. It's in medical references going back as far as 1970s.