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The Centers for Disease Control and Prevention (CDC) has issued a notice about increased influenza activity and its clinical implications as well as new recommendations for influenza antiviral drug treatment for all patients with immunodeficiency who develop signs and/or symptoms of influenza.

Influenza activity, predominantly from A(H3N2), has increased significantly in recent weeks, according to the Centers for Disease Control and Prevention (CDC), which has issued a special health advisory. See: https://emergency.cdc.gov/han/han00409.asp

Given the characteristics of this season’s flu, the CDC is recommending, in addition to the flu vaccine for prevention, increased use of neuraminidase inhibitor (NAI) antivirals for treatment.

Quick treatment is crucial and “should not be delayed even for a few hours to wait for the results of testing,” according to the advisory. Treatment works best when started within 2 days of onset but has shown benefit for some patients even when initiated later.

Focus on treatment is important because in past seasons, A(H3N2) has been linked with more deaths and hospitalizations in people aged 65 years and older and young children than in other groups. Also, this year’s vaccine effectiveness may be as low as last year’s, at 32% for A(H3N2), the CDC says.

NAIs have been effective in randomized trials but have been underused with both outpatients and inpatients, the CDC notes. The advisory reminds clinicians that all inpatients and all high-risk patients (whether inpatient or outpatient) who are suspected of having or confirmed to have influenza should be treated.

Those groups include the following:

  • Patients with severe, complicated, or progressive illness, including outpatients with severe or prolonged progressive symptoms or those who develop pneumonia;
  • Children under age 2 years or people 65 years and older, as well as people younger than 19 years who are receiving long-term aspirin therapy;
  • American Indians/Alaska natives;
  • Women who are pregnant or within 2 weeks postpartum;
  • People with suppressed immune systems;
  • Extremely obese people (body mass index of at least 40); and
  • Those living in long-term care facilities.

Treatment is also indicated when flu is suspected or confirmed for “persons with chronic pulmonary (including asthma), cardiovascular (except hypertension alone), renal, hepatic, hematological (including sickle cell disease), and metabolic disorders (including diabetes mellitus), or neurologic and neurodevelopment conditions (including disorders of the brain, spinal cord, peripheral nerve, and muscle such as cerebral palsy, epilepsy [seizure disorders], stroke, intellectual disability [mental retardation], moderate to severe developmental delay, muscular dystrophy, or spinal cord injury),” the CDC advises.

A history of current season influenza vaccination does not exclude a diagnosis of influenza in an ill child or adult. During influenza season especially, high-risk patients should be advised to call their provider promptly if they have symptoms of influenza. To facilitate early initiation of treatment, when feasible, an antiviral prescription can be provided without testing and before an office visit.

Three NAIs are approved by the US Food and Drug Administration and recommended for the 2017-2018 season: oseltamivir (Tamiflu®), zanamivir (Relenza®); and peramivir (Rapivab®).

This CDC Health Advisory is being issued to remind both clinicians and the public that influenza should be high on their list of possible diagnoses for ill patients because influenza activity is increasing nationwide, and advise clinicians that all hospitalized patients and all high-risk patients (either hospitalized or outpatient) with suspected influenza should be treated as soon as possible with a neuraminidase inhibitor antiviral. While antiviral drugs work best when treatment is started within 2 days of illness onset, clinical benefit has been observed even when treatment is initiated later.

Because of the importance of early treatment, decisions about starting antiviral treatment should not wait for laboratory confirmation of influenza. Therefore, empiric antiviral treatment should generally be initiated in symptomatic individuals as soon as possible when there is known influenza activity in the community.

Posted: January 3, 2018