Recent Flu Updates from the CDC

Seasonal influenza activity is high across the country and continues to increase, with the most frequently reported virus being influenza A(H3N2), according to the US Centers for Disease Control and Prevention’s FluView.

While the majority of cases have been A(H3N2), the CDC reported that 21 percent of cases have been A(H1N1), also known as swine flu. Of 130,584 specimens tested in Week 47, 25 percent were positive for the flu. Cumulatively for this flu season, about 12.5 percent of specimens are positive for the flu, the CDC said.

So far this season, the CDC has reported 8.7 million illnesses, 78,000 hospitalizations, and 4,500 deaths attributed to flu. Including the 2 reported influenza-associated pediatric deaths reported this week, the CDC noted there have been 14 pediatric flu deaths so far this season.

“An annual flu vaccine is the best way to protect against flu,” a statement on FluView said. “Vaccination helps prevent infection and can also prevent serious outcomes in people who get vaccinated but still get sick with flu. CDC recommends that everyone ages 6 months and older get a flu vaccine annually. Now is a good time to get vaccinated if you haven’t already.”

The CDC said that the majority of the circulating flu viruses are antigenically similar to the flu viruses included in this season’s flu vaccine. Flu antiviral drugs also exist, the CDC acknowledged, and said they needed to be started where required as early as possible.

The cumulative hospitalization rate in the FluSurv-NET system (measured at 16.6 per 100,000 for this week) is higher than the rate observed at this same week during every previous season since the 2010-11 season, the CDC said.

Additionally, they noted that the number of flu hospital admissions this week nearly doubled compared to last week (19,593 patients in week 47 vs. 11,378 patients in week 46).

Through Week 47, the CDC said that 7.5 percent of patient visits reported through ILINet were due to respiratory illnesses (including a fever, plus a cough, or sore throat) also known as influenza-like illness (ILI). The national baseline for ILI is 2.5 percent, the CDC said, with all 10 regions across the country being observed above their respective baselines, they said. Due to multiple respiratory viruses co-circulating, the CDC said, the relative contribution of flu virus to ILI varies by location. The CDC also reminded readers that they are tracking the COVID-19 pandemic in a separate weekly publication, the COVID Data Tracker Weekly review.

The CDC said 2 jurisdictions experienced “moderate” ILI activity and 47 jurisdictions experienced “high” or “very high” activity. The only areas depicted with “low” or “minimal” activity were Alaska, Michigan, the US Virgin Islands, Vermont, New Hampshire, and the Northern Mariana Islands.

Long-term care facilities are reporting from all 50 states and through week 47, 2.6 percent of such facilities reported at least one positive flu test among their residents. These facilities, which number nearly 14,000 reporters into the system, account for nursing homes, skilled nursing, long term care facilities for the developmentally disabled, and assisted living facilities.