#16,478
Today's FluView Report - delayed 3 days due to the Holidays - shows a sharp increase in flu activity, particularly across the southern tier of states. While some parts of the country are still reporting minimal ILI activity, 19 jurisdictions are reporting either High or Very High Activity.
ILI rates are above the National baseline (see chart above) for the 3rd week in a row, and have chalked up their biggest weekly increase of this 2021-2022 flu season to date.
In Week 51 influenza A makes up more than 99% of the flu cases detected, and H3N2 makes up > 99% of the influenza A viruses identified.
While early concerns have been raised over this year's vaccine match to the H3N2 virus in circulation (see Preprint: Antigenic & Virological properties of an H3N2 Variant That Will Likely Dominate the 2021-2022 Influenza season) - it is still expected to lower the risks of severe illness - and is very much worth getting.
Key Points
- Influenza activity is increasing, with the eastern and central parts of the country seeing the majority of viruses reported and the western part of the country reporting lower levels of influenza virus circulation.
- The majority of influenza viruses detected are A(H3N2). Most influenza A(H3N2) infections have occurred among children and young adults ages 5-24 years; however, the proportion of infections occurring among adults age 25 years and older has been increasing.
- While there are little data to date, 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 percentage of outpatient visits due to respiratory illness is trending upwards and is above the national baseline. Influenza is contributing to levels of respiratory illness, but other respiratory viruses are also circulating. The relative contribution of influenza varies by location.
- Hospitalizations for influenza are starting to increase.
- The flu season is just getting started. There’s still time to get vaccinated. An annual flu vaccine is the best way to protect against flu and its potentially serious complications. CDC recommends everyone 6 months and older get a flu vaccine.
- There are early signs that flu vaccination uptake is down this season compared to last.
- Flu vaccines are available at many different locations, including pharmacies and health departments. With flu activity just getting started, there is still time to benefit from flu vaccination this season. Visit www.vaccines.gov to find a flu vaccine near you.
- There are also flu antiviral drugs that can be used to treat flu illness.
Increasing influenza around the nation also coincides with a rapid rise in the Omicron COVID variant, and that can make diagnosis of either infection more difficult. Additionally, there are concerns over the potential for seeing dual infections, which have been linked to more severe illness.
While the COVID vaccine (and booster), the flu vaccine, the wearing of face masks, and social distancing may individually provide less-than-perfect protection against infection or illness - when combined - they can substantially reduce your risk of serious illness.
Given that hospitals and emergency services are likely to overwhelmed in the months ahead (see More U.S. Hospitals Inch Towards Invoking Crisis Standards of Care), anything you can do to reduce your risk of either COVID or Flu infection would be of considerable advantage.
