As COVID-19 raged last year, the seasonal flu all but vanished, according to data from the CDC. During the 2019 flu season from Sept. 29 to Dec. 28, the CDC reported more than 65,000 cases of influenza nationwide. During the same period this flu season, the agency reported 1,016 cases. Health experts said that high vaccination rates against the flu – combined with social distancing, mask-wearing and hand-washing employed to stop the spread of the coronavirus – played a huge role in preventing influenza transmission.