During September 1, 2020-April 30, 2021, the California Department of Public Health, Richmond, California, USA, received 255 positive influenza molecular test results that matched with severe acute respiratory syndrome coronavirus 2 molecular test results; 58 (23%) persons were co-infected. Influenza activity was minimal in California, and co-infections were sporadic.
Keywords: COVID-19; California; SARS-CoV-2; United States; co-infections; coronavirus disease; influenza; respiratory infections; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.