Influenza Health Advisory

Published:  October 2, 2017

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Actions Requested of All Clinicians

  1. Encourage and facilitate flu vaccination for everyone age 6 months and older, and encourage and facilitate pneumococcal vaccination for those at increased risk of pneumococcal disease.
  2. Encourage all persons with influenza-like illness (ILI)* who are at increased risk for complications to seek medical care promptly.
  3. Treat all hospitalized patients with clinical signs and symptoms consistent with influenza. Use oseltamivir, zanamivir or peramivir.
  4. Send respiratory specimens (from both upper and lower respiratory tract) for confirmatory PCR influenza testing on all hospitalized patients with clinical signs and symptoms consistent with influenza, especially those in the ICU or fatalities. Sonoma County Public Health laboratory can provide PCR testing. Rapid tests should not be used in this setting.
  5. Report to Sonoma County Public Health Disease Control (707) 565-4566
    • - outbreaks of undiagnosed ILI* in residents of large group or institutional settings; and
    • -individual lab-confirmed cases
  6. Implement infection control precautions as described below. 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 and cough should wear a face mask in common areas of all health care settings.
    • 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 OR for 5 days of treatment.

*ILI (influenza-like illness) is temperature >37.8°C or 100°F and cough and/or sore throat, in the absence of a known cause.

Situational Update

Influenza activity within Sonoma County and California is currently low; however, some local healthcare providers are beginning to diagnose influenza. For weekly CDPH surveillance updates which will be available soon, go to: https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Immunization/Influenza.aspx, and under "Surveillance Reports" click on the most recent report.

Influenza Surveillance and Reporting

Goals for influenza surveillance this season are to: (a) prevent and curb outbreaks in confined settings where the risk of transmission is high; and (b) monitor the epidemiology of severe and fatal cases of influenza.


  • Cases occurring among residents of group or institutional settings (e.g., long-term care, rehab, assisted living facilities, college dorms) in Sonoma County which are either: (a) lab-confirmed cases of influenza or (b) outbreaks of undiagnosed ILI.
    • Report by telephone to (707) 565-4566 within 24 hours
  • Severe and fatal cases of lab-confirmed influenza in persons 0-64 yrs.

Severe case: lab-confirmed influenza in persons 0-64 yrs. hospitalized in the ICU

Fatal case: lab-confirmed influenza in persons 0-64, whether hospitalized or not

Influenza Testing, Specimen Collection and Submission

Rapid antigen tests may be useful when testing to help guide acute clinical care decisions. Reliability of tests varies. Note that a CDC study found that rapid flu tests have limited ability to detect variant influenza A viruses. Further information can be found at: http://www.cdc.gov/flu/professionals/diagnosis/clinician_guidance_ridt.htm . The Sonoma County Public Health Laboratory can perform additional testing by Polymerase Chain Reaction (PCR).

Influenza specimen collection and submittal instructions can be found at: http://sonomacounty.ca.gov/Health/Public-Health/Laboratory/Forms/.

For testing questions, call (707) 565-4711.

Vaccine for Influenza

The 2017-18 Trivalent vaccine contains an A/Michigan/45/2015 (H1N1)pdm09-like virus, an A/Hong Kong/4801/2014 (H3N2)-like virus; and a B/Brisbane/60/2008-like virus (Victoria lineage). Quadrivalent vaccines contain these antigens and also include a B/Phuket/3073/2013-like virus (Yamagata lineage).

There are two new quadrivalent vaccines: one inactivated vaccine, Afluria Qudrivalent IIV and one recombinant vaccine, Flublok Qudrivalent RIV. The age recommendation for Flulaval Quadrivalent has been changed from 3 years old and older to 6 months and older. The age recommendation also changed for the trivalent formulation of Afluria from 9 years old and older to 5 years old and older. Flumist (LAIV) continues to not be recommend, by CDC, this 2017-18 season. A complete listing of 2017-18 flu vaccine products is posted at https://www.cdc.gov/mmwr/volumes/66/rr/pdfs/rr6602.pdf.


Annual vaccination is recommended for everyone age 6 months and older who does not have contraindications, regardless of risk group. For persons whom more than one product is appropriate, no preferential recommendation is made for one product over another. An age appropriate vaccination should be used.

  • Children age 6 months through 8 years need 2 doses for 2017-18, administered at least 4 weeks apart. Children 6 months to 8 years getting vaccinated for the first time and those who have only previously gotten one dose, should get two doses this season. All children who have previously gotten two doses only need one dose this season.
  • Pregnant women may now receive any licensed, recommended, and age-appropriate flu vaccine.
  • Children age 6 through 35 months must receive flu vaccine free of the preservative thimerosal, according to California law.
  • Persons who report an allergy to eggs: No change from 2016-17 season recommendations www.cdc.gov/flu/protect/vaccine/egg-allergies.htm

ACIP recommendations for 2017-18: https://www.cdc.gov/mmwr/volumes/66/rr/rr6602a1.htm

Pneumonia Vaccine Age

Vaccine Information. The pneumococcal conjugate vaccine, PCV13 or Prevnar 13®, is currently recommended for all children younger than 5 years old, all adults 65 years or older, and people 6 through 64 years old with certain medical conditions.

Health Care Workers

By order of the County of Sonoma Health Officer dated October 2, 2017 (originally issued on October 19, 2012), all health care workers at hospitals, skilled nursing facilities (SNFs), residential care facilities for the elderly (RCFEs), residential facilities for the developmentally disabled, and dialysis centers are required to receive an annual influenza vaccination or, if they decline, wear a mask in patient care areas during the influenza season. The full document is available at: http://sonomacounty.ca.gov/WorkArea/DownloadAsset.aspx?id=2147549173. In addition, CA law (Health & Safety Code §1288.7 / Cal OSHA §5199) mandates either flu vaccination or the signing of a declination form for all acute-care hospital workers and most health care personnel including clinic and office-based staff.

Masking Order FAQ (PDF: 167 Kb)

Antiviral Treatment for Influenza

Antiviral medications can reduce illness severity, shorten duration of illness and length of hospitalization, and reduce risk of complications and mortality from influenza. Antiviral medications can also prevent disease. CDC guidelines for influenza antiviral use during 2017 - 18 season are not yet available but are expected in the next several weeks and will be located here: https://www.cdc.gov/flu/professionals/index.htm . We do not anticipate significant changes from 2016-17 recommendations which include:

  • Use of three of the five licensed prescription influenza antiviral agents available in the US: oral oseltamivir (Tamiflu®), inhaled zanamivir (Relenza®), and intravenous peramivir (Rapivab®). All three are neuraminidase inhibitors that have activity against both influenza A and B.

Antiviral treatment as early as possible for suspected or confirmed influenza in:

  • Hospitalized patients;
  • Persons with severe, complicated, or progressive illness; and
  • Persons at higher risk for influenza-related complications.

Those at higher risk for influenza-related complications include:

  • persons age <2 years or = 65 years;
  • persons with chronic pulmonary, cardiovascular, renal, hepatic, hematological, neurologic (including neurodevelopmental), and metabolic disorders;
  • persons with immunosuppression, including from medications or by HIV infection;
  • women who are pregnant or postpartum (within 2 weeks after delivery);
  • persons aged <19 years who are receiving long-term aspirin therapy
  • American Indians/Alaska Natives;
  • persons who are morbidly obese (i.e., BMI =40); and
  • residents of nursing homes and other chronic-care facilities.

Infection Control Precautions for Healthcare Settings

All healthcare facilities should adopt standard and droplet precautions when caring for patients with ILI, or suspected or confirmed influenza infection. Specifically:

  • Request that all persons with fever and cough wear a face mask in common areas of healthcare settings;
  • Isolate unmasked patients with ILI as soon as possible, ideally in a private exam room or at a distance of at least 3 feet from others;
  • Staff entering the exam room of any patient with ILI should either ensure the patient is masked, or wear either a face mask or N-95 respirator pending diagnosis.
  • CDC infection control guidance for the 2017 – 18 season is not yet available, but is expected in the next several weeks and will be located here: https://www.cdc.gov/flu/professionals/index.htm . We do not anticipate significant changes.

There are no data to indicate that the transmission characteristics of the swine variant influenza viruses (e.g., H1N2v or H3N2v) differ from those of seasonal influenza viruses. The infection control principles and actions relevant for seasonal influenza are appropriate for the control of the swine variant influenza virus infections.

If avian influenza A (H7N9 or H5N1) or MERS-CoV are suspected: use standard, contact and airborne precautions. For more information on infection control when novel avian influenza A virus infections are suspected, see: http://www.cdc.gov/flu/avianflu/novel-flu-infection-control.htm. For more information on infection control when MERS-CoV is suspected see http://www.cdc.gov/coronavirus/mers/infection-prevention-control.html.

Solicitation for Sentinel Providers for Influenza Surveillance

Primary care providers are invited to enroll as sentinel providers for influenza surveillance in Sonoma County. Compiling and reporting data usually takes less than 30 minutes per week. If interested in participating, contact the California Department of Public Health at influenzasurveillance@cdph.ca.gov or (510) 620-3737.

Additional Resources

Sonoma County Public Health: www.sonoma-county.org/flu

CDPH: https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Immunization/Influenza.aspx

CDC: http://www.cdc.gov/flu

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