Early and Intense Flu Season Revs Up

The Centers for Disease Control and Prevention’s (CDC) November 28 update for influenza shows the predictions of a difficult flu season based on the southern hemisphere’s experience are coming to fruition. In addition, children’s hospitals continue to be overwhelmed with respiratory syncytial virus, and COVID-19 is slowly rising.

The Total Tally So Far

The latest flu update reports that so far, the season has tallied 2900 total deaths, 53,000 hospitalizations, and at least 6.2 million illnesses from influenza.

Flu Activity

Only 6 states or territories report low flu activity: Vermont, New Hampshire, the North Mariana Islands, Alaska, Michigan, and South Dakota. Thirty-five states report high or very high rates of influenza, with Texas, New Mexico, and Tennessee reporting the highest levels for the past week. Rates of influenza are going down in southeastern states and plateauing in the south-central region.

Strains

Lab samples have risen from a 14.7% to an 18.2% positivity rate , with A(H3N2) being the most frequently reported virus.¹ “Of influenza A viruses detected and subtyped this season, 78% have been influenza A(H3N2) and 22% have been influenza A(H1N1),” the CDC reports. All pediatric deaths have been from influenza A.¹ Two deaths were subtyped, with 1 being classified as A(H1N1)pdm09 and the second as an A(H3) type.¹

Hospitalizations

The FluSurv-NET system reported the cumulative hospitalization rate is 11.3 per 100,000, “higher than the rate observed in week 46 during every previous season since 2010-2011.” The CDC said that 11,269 patients were admitted to a hospital for lab-confirmed flu.¹

Mortality

There have been 12 total pediatric deaths, of which 41% (5) occurred in the past week. Pediatric deaths for previous flu seasons were 2019-2020 (199 deaths); 2020-2021 (1 death); 2021-2022 (44 deaths). The CDC reported a total of 1861 pneumonia, influenza, and/or COVID related deaths for the previous week, accounting for 9.4% of total mortality. Of these, 66 were classified as influenza, and the CDC noted that “while current PIC mortality is due primarily to COVID-19, the proportion due to influenza remains small but is increasing.”

Vaccinations

In a CDC media telebriefing about circulating respiratory diseases given on November 4th, Jose Romero, MD, FAAP, FIDSA, FPIDS, FAAAS, director of the National Center for Immunization and Respiratory Diseases said that the H3N2 strains are known for being more severe in children and the elderly, and that “there are also early signs of influenza causing severe illness in precisely these 2 groups of individuals this season.”² However, this season’s flu vaccine continues to be a good match for circulating strains.¹ “The majority of influenza viruses tested are in the same genetic subclade as and antigenically similar to the influenza viruses included in this season’s influenza vaccine,” the CDC reported.

Vaccination is highly recommended for everyone 6 months of age and older, and it is not too late to get vaccinated. Pharmacists can help fight flu this season by checking in with patients to see if they have received their annual flu shot. In particular, they can look out for young and elderly patients by prioritizing asking parents and seniors if they need a flu shot when visiting the pharmacy. In addition, pharmacists can recommend antivirals for patients infected to reduce the risk of negative outcomes.

References

1. Weekly US influenza surveillance report. Report. CDC. Updated November 28, 2022. Accessed November 29, 2022. https://www.cdc.gov/flu/weekly/index.htm.
2. CDC media telebriefing: update on respiratory disease circulation transcript. Transcript. CDC. November 4, 2022. Accessed November 29, 2022. https://www.cdc.gov/media/releases/2022/t1104-update-respiratory-disease-circulation.html.