Unfortunately, as we are seeing this year, the flu did not disappear. The measures taken to prevent COVID-19, such as masking, hand washing and social distancing, are also great ways to prevent influenza. Additionally, during the 2020-2021 flu season, arecord number of influenza vaccines were distributed. Throughout history, it is common to see a decrease in a disease with the rise of another disease. Historiansrefer to these as disease cycles and they have had major impacts on human history.