If you have any questions regarding clinical testing for avian Influenza A(H5N1) viruses at PHEL, please contact phel.influenza@doh.nj.gov

Currently circulating seasonal influenza A subtypes include (A)H1N1 and (A)H3N2.  Strains of avian Influenza A(H5N1) have been circulating in wild birds and domestic poultry, as well as sporadic mammalian infections since 2022.  Starting in 2024, circulation of these viruses has been identified in dairy cattle, and human cases have also been reported.  CDC maintains that the current risk these viruses pose to the public remains low, and continues to monitor the situation.

NJ PHEL has released two communications to clinical and commercial laboratories regarding avian Influenza A(H5N1) in response to Health Alert Network (HAN) messages sent out by CDC.

• NJ PHEL | Flu Update #2 | February 26, 2025 (most current guidance)
  • NJ PHEL | Flu Update | January 31, 2025
  • NJ LINCS Message: Accelerated Subtyping of Influenza A in Hospitalized Patients | NJ DOH

• NJ PHEL | HPAI H5N1 Update | April 18, 2024
  
  • CDC HAN-00506 Highly Pathogenic Avian Influenza A(H5N1) Virus: Identification of Human Infection and Recommendations for Investigations and Response

For more information regarding avian Influenza A(H5N1), refer to the CDC's website here: H5 Bird Flu: Current Situation

Additional New Jersey- specific resources regarding avian Influenza A(H5N1) are available here: NJ H5N1 Bird Flu Resources

Immediately submit any influenza specimen that tests positive for influenza A but tests negative A virus but negative for seasonal influenza A subtypes [i.e., A(H1) and A(H3)] (a.k.a. Unsubtypeable influenza A).

There is no need for prior authorization to submit an unsubtypeable influenza specimen.

Specimens should be submitted to PHEL within 24 hours of obtaining subtyping results.

What is an Unsubtypeable Influenza A Specimen?

• Any specimen that tests positive for influenza A but tests negative A virus but negative for seasonal influenza A subtypes [i.e., A(H1) and A(H3)].
• This may also be referred to as an "unsubtypeabeable" influenza A specimen, or "Influenza A, subtype not detected".

• To be considered unsubtypeable:
  • Specimens have been tested on a molecular assay which can detect currently circulating influenza A virus subtypes (i.e. “seasonal influenza” subtypes).
  • Do not submit specimens which are not tested for influenza subtype.
  • Do not submit specimens which are inconclusive or equivocal for Influenza A infection.

How to submit an Unsubtypeable Influenza Test to PHEL

There is no need for prior authorization to submit an unsubtypeable influenza specimen. To submit:

1. Select the test choice ‘Respiratory Virus Surveillance (Influenza + COVID-19), either online through our electronic ordering portal or on the SRD-1 form. 
   • Online, there is a drop-down question asking why you are submitting. Select the option "Non H1/H3 Influenza A (unsubtypeable)".
   • If you are using a paper form, write in the comments that this specimen was tested as unsubtypeable influenza A.
2. As a courtesy, we request you email phel.influenza@doh.nj.gov and phel.specimenreceiving@doh.nj.gov that you are sending an unsubtypeable specimen, so that it can be processed promptly on arrival.
   • Include in the email a specimen identifier, point of contact and expected delivery date.

Maintain Specimen Integrity

Unsubtypeable results may be caused by factors not limited to novel influenza infection, such as assay sensitivity, low viral titers, or poor specimen quality.  Virus in a specimen may degrade over time if kept refrigerated, or if frozen and thawed repeatedly. Therefore, maintaining frozen temperatures is critical to maintaining specimen integrity.

• If you are unsure whether a specimen needs to be sent to PHEL, we prefer you freeze the specimen as soon as possible after collection and maintain frozen temperatures during shipping.

• Avoid freeze thaw cycles.

• Submission of residual specimen volume is acceptable, but laboratories may also consider sending an aliquot (at least 0.5mL) in a secondary tube labeled with 2 patient identifiers (e.g. name and DOB) that is kept frozen.

• Storage temperature must be maintained during shipping. 

• • If unable to ship on dry ice, ensure enough cold packs are used so that the specimen does not thaw during transit.

• Testing should be performed on persons who meet Epidemiologic criteria AND either Clinical OR Public Health Response criteria as outlined in the Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations

• Before sending samples to PHEL, contact the local health department or communicable disease service to obtain testing authorization. PHEL will not test specimens received without authorization.

• For persons with suspected HPAI A(H5N1) virus infection, the following specimens should be collected as soon as possible after illness onset or when deemed necessary:

• • If the person has conjunctivitis (with or without respiratory symptoms), both a conjunctival swab and nasopharyngeal swab should be collected.

• • A nasopharyngeal swab and a nasal swab combined with an oropharyngeal swab (e.g., two swabs combined into one viral transport media vial).

• • • If these specimens cannot be collected, a single nasopharyngeal or oropharyngeal swab is acceptable. 

• • Patients with severe respiratory disease also should have lower respiratory tract specimens (e.g., an endotracheal aspirate or bronchoalveolar lavage fluid) collected, if possible.

Current guidance from CDC is to perform accelerated subtyping of patients hospitalized with influenza A infection. 

Hospital laboratories should:

• Perform an influenza subtyping test that identifies seasonal influenza A subtypes (H1N1 and H3N2) on hospitalized patients with confirmed influenza A infection.
• Decrease turnaround time for subtyping tests. Ideally, subtyping results should be available within 24 hours.

If a laboratory is unable to perform in-house subtyping on hospitalized influenza A patients, PHEL recommends:

• Utilize testing available through commercial laboratories when possible.
• Prioritize subtyping severe cases, especially all individuals in an intensive care unit (ICU).
• Prioritize subtyping of influenza specimens for any cases with epidemiological risk factors, such as exposure to poultry, dairy cattle, consumption of raw milk- see the CDC HAN-00520 for full criteria.

If subtyping is unavailable through any of the mechanisms above, PHEL is able to test a subset of respiratory samples. You can submit to PHEL:

• All ICU patients for whom subtyping is not able to be performed
• Up to 5 inpatient samples a week
• Any unsubtypeable influenza specimens

Email phel.influenza@doh.nj.gov to notify us that your facility will be utilizing testing at PHEL in advance of your first shipment.

General Laboratory Guidance

• Collect specimens aseptically as soon as possible after symptom onset.

• For detailed instructions on how to collect respiratory specimens see here: Respiratory Specimen Collection Quick Guide.

• Proper infection control practices should be followed during specimen collection.

• All specimens should be labeled clearly with two patient identifiers (e.g. name and DOB) and include a printed paper requisition form with all required information in the package.

• If you are unsure whether a specimen needs to be sent to PHEL immediately, we prefer you freeze the specimen as soon as possible after collection and maintain frozen temperatures during shipping.

Specimen Types

The preferred respiratory specimen type for most respiratory viral testing is a nasopharyngeal swab collected into 1-3 mL of viral transport media.   

• Additional specimen types may also be recommended based on the test requested. 

• • PHEL accepts: Nasopharyngeal (NP) swabs, Conjunctival swabs, Oropharyngeal (OP) swab, Combined Nasopharyngeal and Oropharyngeal swabs, Nasal mid turbinate swabs, Anterior nasal swabs, Nasopharyngeal wash/aspirate, nasal wash/aspirate, Bronchoalveolar lavage, tracheal aspirate, pleural fluid.

• • Sputum and lung biopsy specimens may be accepted but cannot be tested at PHEL and will need to be forwarded to CDC for testing.

• All swabs should be placed in a transport tube containing 1-3mL viral transport Media (VTM).

• Swab specimens should be collected using swabs with a synthetic tip (e.g., polyester or Dacron®) and an aluminum or plastic shaft. Swabs with cotton tips and wooden shafts are not recommended. Specimens collected with swabs made of calcium alginate are not acceptable.

• Submission of residual specimen volume is acceptable. 

• • Laboratories may also consider sending an aliquot (at least 0.5mL) in a secondary tube labeled with 2 patient identifiers (e.g. name and DOB) that is kept frozen.

Storage and Shipping Information:

Store specimens refrigerated (2-8°C) for no longer than 72 hours from time of collection. If specimen submission and receipt at NJ PHEL will take more than 72 hours, freeze specimens at -70°C or below and ship on dry ice.

• Storage temperature must be maintained during specimen transport (via courier or overnight shipping). If not able to maintain frozen temperature during entire transport (i.e. on dry ice), shipping on frozen cold packs is acceptable. Avoid freeze-thaw cycles.