CDC Health Advisory Regarding the Potential for Circulation of Drifted Influenza a (H3N2) Viruses [December 03, 2014, 16:00 ET (4:00 PM ET)]

Details

• Corporate Authors:
  Centers for Disease Control and Prevention (U.S.). Health Alert Network (HAN)
• Description:
  December 03, 2014, 16:00 ET (4:00 PM ET)
  
  CDCHAN-00374
  
  CDC is reminding clinicians of the benefits of influenza antiviral medications and urging continued influenza vaccination of unvaccinated patients this influenza season.
  
  Summary: Influenza activity is currently low in the United States as a whole, but is increasing in some parts of the country. This season, influenza A (H3N2) viruses have been reported most frequently and have been detected in almost all states.
  
  During past seasons when influenza A (H3N2) viruses have predominated, higher overall and age-specific hospitalization rates and more mortality have been observed, especially among older people, very young children, and persons with certain chronic medical conditions compared with seasons during which influenza A (H1N1) or influenza B viruses have predominated.
  
  Influenza viral characterization data indicates that 48% of the influenza A (H3N2) viruses collected and analyzed in the United States from October 1 through November 22, 2014 were antigenically "like" the 2014-2015 influenza A (H3N2) vaccine component, but that 52% were antigenically different (drifted) from the H3N2 vaccine virus. In past seasons during which predominant circulating influenza viruses have been antigenically drifted, decreased vaccine effectiveness has been observed. However, vaccination has been found to provide some protection against drifted viruses. Though reduced, this cross-protection might reduce the likelihood of severe outcomes such as hospitalization and death. In addition, vaccination will offer protection against circulating influenza strains that have not undergone significant antigenic drift from the vaccine viruses (such as influenza A (H1N1) and B viruses).
  
  Because of the detection of these drifted influenza A (H3N2) viruses, this CDC Health Advisory is being issued to re-emphasize the importance of the use of neuraminidase inhibitor antiviral medications when indicated for treatment and prevention of influenza, as an adjunct to vaccination.
  
  The two prescription antiviral medications recommended for treatment or prevention of influenza are oseltamivir (Tamiflu®) and zanamivir (Relenza®). Evidence from past influenza seasons and the 2009 H1N1 pandemic has shown that treatment with neuraminidase inhibitors has clinical and public health benefit in reducing severe outcomes of influenza and, when indicated, should be initiated as soon as possible after illness onset. Clinical trials and observational data show that early antiviral treatment can:
  
  • shorten the duration of fever and illness symptoms;
  
  • reduce the risk of complications from influenza (e.g., otitis media in young children and pneumonia requiring antibiotics in adults); and
  
  • reduce the risk of death among hospitalized patients.
  
  
• Content Notes:
  Notice of Possible Alert Expiration: The CDC Health Alert, Advisory, Update, and Info Service announcements, distributed by the Health Alert Network (HAN), were active on the date they were originally published. Publication dates have been added to Titles for clarity. A CDC Health Alert, Advisory, Update, and Info Service announcement may expire at any time. They may also be updated or superseded according to later developments. None of the CDC Health Alert, Advisory, Update, or Info Service announcements in the Stacks HAN Collection should be assumed to be current or active. Stacks preserves HAN announcements in order to maintain a record of past CDC actions. Stacks in not designed for up-to-the-minute notifications. For the list of current CDC Health Alert, Advisory, Update, or Info Service announcements, patrons should visit the Health Alert Network (HAN) webpage at https://www.cdc.gov/han/php/about/index.html. For up to the minute reports, subscribe to the HAN email alert system hosted by CDC News & Updates at https://tools.cdc.gov/campaignproxyservice/subscriptions.aspx?topic_id=USCDC_486
  
  Categories of Health Alert Network (HAN) messages:
  
  Health Alert: Requires immediate action or attention, highest level of importance.
  
  Health Advisory: May not require immediate action; provides important information for a specific incident or situation.
  
  Health Update: Unlikely to require immediate action; provides updated information regarding an incident or situation.
  
  HAN Info Service: Does not require immediate action; provides general public health information.
  
  
• Subjects:
  Influenza, Human Influenza A Virus, H3N2 Subtype
• Keywords:
  HAN Health Alert Network
• Source:
  HAN ; 374
• Series:
  Health Alert Network
• Subseries:
  CDC Health Advisory
• Publisher:
  Centers for Disease Control and Prevention (CDC) (U.S.)
• Document Type:
  Text
• Genre:
  Alert
• Place as Subject:
  United States
• Rights:
  Public Domain
• Pages in Document:
  2 unnumbered pages
• Issue:
  00374
• Collection(s):
  Health Alert Network (HAN)
• Main Document Checksum:
  urn:sha-512:38d440f3cc37a89952c2a710472e1c3a4567e85f6c5bfbdf9ec19cba34740fce5a711af62536ca1de9a4b61f7674d0fec7c3930779e12ca578c2ad788d30a9a1
• Download URL:
  https://stacks.cdc.gov/view/cdc/26196/cdc_26196_DS1.pdf
• File Type:
  [PDF - 1.58 MB ]