There were an increase in outbreaks, flu related deaths, and I believe hospitalizations around the end of the year in California when comparing 2018 to 2019. 2

There were an increase in outbreaks, flu related deaths, and I believe hospitalizations around the end of the year in California when comparing 2018 to 2019. 2018 https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/Immunization/Week2018-1952_FINALReport.pdf https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20... 2019 https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20Library/Immunization/Week2019-2052_FINALReport.pdf https://www.cdph.ca.gov/Programs/CID/DCDC/CDPH%20Document%20... I could be just the flu, but it could also be the start of something else circulating with the flu. Even in that case odds are that something else was not covid-19, but it could be. The only way to tell would be to test blood collected at the time for serological evidence of covid-19.