Update to Influenza Health Advisory

Published:  December 29, 2017

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Situational Update

Influenza activity is rapidly increasing throughout California including Sonoma County. The Centers for Disease Control (CDC) has identified influenza A(H3N2) as the predominate strain so far this season. In the past, influenza A(H3N2) virus-predominant seasons have been associated with more hospitalizations and deaths in person aged 65 years and older and young children compared to other age groups.   

Additionally, vaccine effectiveness against influenza A(H3N2) in general has been lower than against influenza A(H1N1)pdm09 or influenza B viruses.  If influenza A(H3N2) continues to be the predominant strain the use of antivirals becomes even more important than usual.  

To date this season in Sonoma County, respiratory outbreaks in several long term care facilities and increased hospitalizations including 4 severe cases in individuals less than 65 years of age have been reported. Influenza B is also circulating in the region.  Implementation of appropriate infection control precautions is critical.   

Weekly California Department of Public Health Updates
(Under "Surveillance Reports" click on the most recent report)

Actions Requested of All Clinicians

Encourage and facilitate FLU VACCINATION for all persons aged 6 months and older, AND PNEUMOCOCCAL VACCINATION for those at increased risk of pneumococcal disease.

  1. Encourage all with ILI* who are at increased risk for complications to seek medical care promptly.
  2. Treat all hospitalized patients and those with severe or progressive illness with clinical signs and symptoms consistent with influenza. Also strongly consider antiviral treatment for non-hospitalized individuals at high risk for complications. Use a neuraminidase inhibitor such as oseltamivir, zanamivir or peramivir.
  3. Send respiratory specimens (from both upper and lower respiratory tract) for confirmatory PCR influenza testing on all hospitalized patients with illness consistent with influenza, especially those in the ICU or fatalities.  The Public Health lab can do PCR testing.
  4. Report to Sonoma County Public Health (PH) Disease Control (707) 565-4566
    • outbreaks of undiagnosed ILI* in residents of large group or institutional settings; and
    • individual lab-confirmed cases of seasonal influenza only if: severe and fatal cases of lab-confirmed influenza in persons 0 - 64 years OR cases of ILI with epidemiological characteristics suggesting variant OR novel influenza infection OR MERS.
  5. Implement infection control precautions described in Oct 2016 Influenza Health Advisory. Note:
    • ALL PERSONS with ILI* should be instructed to stay at home until 24 hours after fever resolves, except patients that require medical evaluation and care.
    • ALL PERSONS with fever & cough should wear a face mask in common areas of health care sites.
    • All hospitalized patients with suspected or confirmed flu should remain in isolation for 7 days after illness onset OR until 24 hours after fever resolution, whichever is longer.  If a patient is clinically ready for discharge, isolation status should not be a barrier.
  6. Consult with PH Disease Control (707) 565-4566 if you facility is experiencing an influenza outbreak or if your hospital is experiencing difficulty discharging patients.

Additional Resources

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Santa Rosa, CA 95404
38.441691, -122.713746

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