CDC Seasonal Influenza A(H3N2) Activity and Treatment Advisory

influenza virus
influenza virus
Recent significantly increased influenza activity prompts CDC advisory for antiviral treatment.

The Centers for Disease Control and Prevention (CDC) Health Alert Network has issued an advisory regarding increased influenza A(H3N2) activity this flu season.

The H3N2 strain is predominating this flu season, which in the past has led to increased hospitalizations and deaths in patients aged 65 years and older and young children vs the general population. The CDC therefore cautions physicians that influenza should be high on the list of possible diagnoses for sick patients, and all hospitalized, severely ill, and high-risk patients with suspected or confirmed influenza should begin treatment with a neuraminidase inhibitor antiviral as soon as possible. Healthcare providers have also been informed that waiting for testing confirmation is not necessary in suspected cases because timing of treatment can have significant positive effects on outcome.

Vaccination remains recommended for all with antivirals as an adjunct in suspected and confirmed cases. Antivirals are also recommended for non–high-risk patients with uncomplicated flu, as treatment may reduce illness by one day.

Three prescription neuraminidase inhibitor antiviral medications are currently approved and recommended by the US Food and Drug Administration (FDA): oseltamivir (available as a generic version or under the trade name Tamiflu®), zanamivir (Relenza®), and peramivir (Rapivab®). Use of oseltamivir for chemoprophylaxis is not recommended in patients’ <3 months, unless the situation is deemed critical. Zanamivir is not recommended for hospitalized patients as limited data in such use are available; however, it is approved for treatment of uncomplicated influenza within 2 days of illness in patients ≥7 years or for prevention of flu in persons ≥5 years. Adamantanes (rimantadine and amantadine) are not currently recommended for treatment or chemoprophylaxis due to high resistance of circulating influenza A strains.

Additional considerations for physicians include a reminder that early diagnosis with influenza can reduce inappropriate antibiotic use; however, as bacterial infections are a common complication of influenza, they should be considered and appropriately treated with antibiotics when suspected.

Additional information for patients is available from CDC at

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Seasonal influenza A(H3N2) activity and antiviral treatment of patients with influenza [press release]. Atlanta, Georgia: Centers for Disease Control and Prevention. Published December 27, 2017. Accessed January 17, 2018.