Updated guidance for clinical consideration of Avian Influenza

Situation

• This message provides updated guidance on highly pathogenic avian influenza exposure screening and testing, as well as clarification on influenza subtyping guidance.
• In November of this year, WA DOH confirmed the first known human case of H5N5 avian influenza. The patient was hospitalized with severe disease that unfortunately resulted in death.
• Symptoms of avian influenza in humans can range from mild to severe and can be similar to seasonal influenza viruses.
• Centers for Disease Control and Prevention (CDC) and Washington Department of Health (DOH) currently consider the risk from avian influenza to be low for the general public.

Recommendations for healthcare facilities

Screening for potential exposures to avian influenza

• Assess all patients with suspected influenza for potential exposure history to avian influenza. Epidemiologic risk factors include one or more of the following within 10 days before illness onset:
• Direct contact with sick or dead animals, or their environments, including wild birds, backyard poultry, or livestock (such as animal exposures that agricultural and farm workers may encounter)
• Consumption of or direct contact with raw animal products such as raw cow milk and raw pet food
• Close contact with a symptomatic person diagnosed with avian influenza

Testing if you suspect avian influenza

• If you suspect that a patient has avian influenza based on the epidemiologic risk factors above, contact your local health department and obtain Influenza A subtyping (see additional information below). The local health department will help determine if specific testing for avian influenza is recommended.
• The diagnosis of avian influenza in humans can be challenging. A negative influenza result in a patient with epidemiologic risk factors for avian influenza does not rule out avian influenza. If you suspect avian influenza in a hospitalized patient:
• After consultation, your local health department may recommend repeat influenza testing on at least two consecutive days.
• If the patient has severe disease, consider collecting lower respiratory tract specimens for influenza testing. Lower respiratory tract specimens have a higher yield for detecting avian influenza. Test for influenza AND obtain influenza A subtyping (see additional information below).

Obtaining influenza subtyping

• Subtyping should be obtained for patients with epidemiologic risk factors as described above. Subtyping is not being requested for all hospitalized patients.
  • Some facilities might choose to conduct routine subtyping (e.g., all patients with influenza admitted to the ICU).
  • Hospitals and laboratories participating in RESP-NET or sentinel influenza subtyping surveillance should not deviate from established program procedures.
• If influenza subtyping is performed at your facility’s clinical or commercial laboratory, the specimen does not need to be submitted to Washington Public Health Laboratory (WAPHL) unless it is identified as unsubtypeable or as H5 or other novel influenza subtype.
• WA DOH Public Health Laboratories (WAPHL) can support influenza subtyping for facilities without influenza subtyping capabilities.
  Follow specimen submission guidelines for all specimens submitted to WAPHL.

Reporting to Public Health

• Immediately report any of the following to Public Health:
• Suspected or confirmed cases of avian influenza or other novel influenza.
• Influenza A positive specimens that are reported as "unsubtypeable" (when the subtype of influenza cannot be determined by available tests).

Isolation and personal protective equipment for suspected or confirmed avian influenza

• Isolate patients with suspected or confirmed avian influenza in all healthcare settings.
  • If possible, isolate the patient in an airborne infection isolation room (sometimes called a negative pressure room).
  • If the patient is intubated, ensure a closed system and HEPA filter.
• Healthcare workers should use contact and airborne precautions with eye protection, meaning a gown, gloves, respirator (fit-tested N95 or higher level of protection), and goggles or face shield.

Treatment of patients with suspected or confirmed avian influenza

• Treat suspected avian influenza patients immediately with oseltamivir; do not wait for influenza confirmation.
• Consider combination antiviral treatment (e.g., oseltamivir and baloxavir) for hospitalized patients with suspected or confirmed avian influenza.
• Refer to CDC's Interim Guidance on the Use of Antiviral Medications for additional information about treating patients with suspected or confirmed avian influenza.

Information for patients

• Advise people not to handle sick or dead birds or other wildlife.
  • People can report sick or dead wild birds or other wild animals to the Washington State Department of Fish & Wildlife.
  • People can report sick or dead domestic animals, including backyard flocks or livestock suspected of having avian influenza, to the Washington State Department of Agriculture.
• Seasonal influenza vaccine is recommended for everyone 6 months of age and older.
  • Annual flu vaccination is the best way to reduce the risk of severe disease and hospitalization caused by seasonal influenza.
  • While the seasonal influenza vaccine is not intended to protect against avian influenza, it decreases the risk of people getting infected with seasonal influenza and avian influenza at the same time. These potential co-infections are an important public health concern because they could allow avian influenza viruses to gain the ability to spread efficiently from human to human.