Flu Activity Remains Elevated

Although influenza activity declined slightly this week, it remained elevated, according to the weekly U.S. Influenza Surveillance Report from the U.S. Centers for Disease Control and Prevention (CDC).

For the week ending January 8, 2.2% of clinical lab tests were positive for influenza and 4.3% of visits to a health care provider were for respiratory illness, which is above the baseline. Influenza is contributing to levels of respiratory illness, but other respiratory viruses are also circulating.

The majority of influenza viruses detected were A(H3N2). Most of the H3N2 viruses so far are genetically closely related to the vaccine virus, but there are some antigenic differences that have developed as H3N2 viruses have continued to evolve.

The cumulative hospitalization rate for flu is higher than the rate for the entire 2020-2021 season, but lower than the rate seen at this time during the four seasons preceding the COVID-19 pandemic.