CDC Flu Update: Illness Driven by a Wave of H3N2 Virus Activity
According to this week’s FluView report, overall influenza activity decreased slightly but remains high, driven by a wave of H3N2 virus activity. While this week saw small declines in levels of influenza-like-illness (ILI) and the proportion of clinical laboratory specimens testing positive for flu, 46 states and Puerto Rico continue to report widespread flu activity and 30 states are still experiencing high ILI activity. Influenza A(H1N1)pdm09 viruses remain predominant for the flu season nationally, however, during the week ending March 9, influenza A(H3) viruses were reported more frequently that H1N1pdm09 viruses for the second week in a row. Also, another four flu-related pediatric deaths occurring during the 2018-2019 season were reported by CDC, bringing the total to 68 flu-related pediatric deaths this season.
CDC expects flu activity to remain elevated for a number of weeks. While CDC continues to recommend influenza vaccination as long as influenza viruses are circulating, influenza antiviral drugs are an important second line of defense that can be used to treat flu illness. H3N2 viruses are typically associated with more severe illness in older adults, and flu vaccine may protect less well against H3N2 illness in older adults, making prompt treatment with flu antivirals in this age group especially important during the current period of H3N2 predominance.
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