Guidelines for Laboratory Biosafety: Handling and Processing Specimens Associated with Novel Influenza A Viruses, Including Potential A(H5N1) Virus

Introduction

Novel Influenza A viruses are Influenza A viruses that have infected people but are different from seasonal Influenza A viruses currently circulating among humans. This includes highly pathogenic avian influenza (HPAI) A(H5) or A(H7) viruses. Clinical presentation for Novel Influenza A viruses can range from asymptomatic infections to severe disease. For further information on Novel Influenza A viruses that have caused human infections: Reported Human Infections with Avian Influenza A Viruses

Although some diagnostic assays may detect the presence of some Novel influenza A viruses, a negative subtyping result should not be used to rule out Novel influenza A virus infection when a sample is positive for influenza A. Testing of symptomatic human cases of suspected Novel Influenza A virus infection should be referred to the nearest public health laboratory. For more information: Interim Guidance on Testing and Specimen Collection for Patients with Suspected Infection with Novel Influenza A Viruses with the Potential to Cause Severe Disease in Humans

This guidance is intended for clinical laboratory and support staff who handle, or process specimens potentially containing Novel Influenza A viruses, including potential A(H5N1) viruses. For guidance on other specific activities potentially containing Novel Influenza A viruses, including potential A(H5N1) viruses, Updated Interim Recommendations for Worker Protection and Use of Personal Protective Equipment (PPE) to Reduce Exposure to Novel Influenza A Viruses Associated with Disease in Humans

Diagnostic testing

Routine diagnostic testing procedures includes the following activities: initial processing of specimens, using inactivated specimens (e.g., specimens in nucleic acid extraction/lysis buffer), performing FDA-cleared molecular assays [e.g., Real-Time RT-PCR (rRT-PCR)], performing antigen detection tests, final packaging of specimens for transport to a local or state public health laboratory for additional testing (specimens should already be in a sealed, decontaminated primary container), and specimen storage. For biosafety considerations for viral culture: Culturing Specimens for Novel Influenza A Viruses

Clinical and Public Health Laboratories should continue to follow existing handling and processing guidance for specimens from patients suspected with Influenza virus infection, including sending any specimens from patients with suspected Novel Influenza A virus infection to a state health laboratory and alerting CDC immediately if any clinical specimens test positive for Novel Influenza A or if unsubtypeable results are obtained.

Risk assessment and mitigation

All laboratories should perform a site-specific and activity-specific risk assessment to identify and mitigate risks before working with diagnostic specimens. The risk assessment will assist in determining the appropriate selection of microbiological practices, safety equipment (e.g., engineering controls and personal protective equipment [PPE]) and facility safeguards that can help prevent exposures. Risk assessments and mitigation measures are dependent on:

• The procedures performed
• The hazards involved in the processes and procedures
• The competency level of the personnel who perform the procedures
• The laboratory equipment and facility
• The resources available

It is recommended that biosafety professionals, institutional safety committees, laboratory management, laboratory personnel, and scientific safety experts be involved in the risk assessment process.

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Biosafety Considerations for Diagnostic Testing:

Facilities that process and test respiratory specimens should have the necessary equipment, engineering controls, PPE, appropriate diagnostic assays, and properly trained personnel.

• Perform routine diagnostic specimen processing and testing in Biosafety Level 2 (BSL-2) laboratory facilities, adhering to standard precautions, safety equipment requirements, and facility specifications recommended for BSL-2, which includes, but are not limited to:
  • Buttoned-down lab coat or solid front gown
  • Eye protection (safety glasses or goggles), face protection (face shield), or combination of both
  • Gloves when handling specimens
  • Proper handwashing procedures
• Manipulate diagnostic specimens in a certified Class II Biosafety Cabinet (BSC) or other containment devices, especially if there is a potential to generate aerosols(e.g., vortexing or pipetting).
• If you cannot perform a procedure within a BSC, use a combination of PPE and other containment devices (e.g., benchtop safety shield, centrifuge safety cups, or sealed rotor) designed to create a barrier between the specimen and the laboratory personnel. Perform site-specific and activity-specific biosafety risk assessments to determine if your situation warrants additional precautions. See precaution guidance below to prevent exposures for procedures with a high likelihood of generating droplets or aerosols.
• Site-specific and activity-specific biosafety risk assessments should be performed to identify the need for additional precautions to reduce exposure risk. These may include, but are not limited to:
  • Double gloves
  • NIOSH Approved® N95® filtering facepiece respirator or higherA
  • Additional administrative controls and/or work practices

Procedures with a high likelihood of generating droplets or aerosols

Many routine laboratory procedures can generate aerosols and droplets that are often undetectable. For example, the following laboratory procedures have been associated with the generation of infectious aerosols and droplets: pipetting, centrifuging, shaking, mixing, sonicating, vortexing, removing caps, aliquoting and loading specimens, spilling specimens, and cleaning up spills.

Procedures with a high likelihood of generating aerosols or droplets should be conducted using a certified Class II BSC or other physical containment equipment. If it is not possible to perform a procedure within a BSC or other physical containment device, a combination of appropriate personal protective equipment (PPE) and administrative controls should be based on a risk assessment.

Culturing specimens for novel influenza A viruses

Culture-based testing or viral isolation should not be performed for Novel influenza A viruses as a routine diagnostic procedure in clinical or diagnostic laboratories due to the potential for these viruses to be related to viruses that have caused severe disease in humans, as described above in the "Background" section of this page.

A subset of Novel Influenza A viruses are considered Select Agents, including Highly Pathogenic Avian Influenza (HPAI) A viruses. Select Agents are regulated by the Federal Select Agent Program. Additional information on Select Agent regulations, policies, and requirements can be found on their website.

Decontamination

Decontaminate work surfaces and equipment with appropriate disinfectants effective against Influenza viruses. The United States Environmental Protection Agency (EPA) has registered Antimicrobial Products Effective Against Avian Influenza [List M]. Users should carefully follow the manufacturer/label directions for the safe use of disinfectants.

All reusable PPE must be properly cleaned and decontaminated according to manufacturer's instructions after each use. All residual specimens, and waste should be decontaminated before on-site disposal using an approved method, such as autoclaving.

Laboratory Waste Management

Decontaminate all potentially infectious materials prior to disposal using an effective method consistent with all local and state requirements. Materials that will be decontaminated outside the immediate laboratory should be placed in a durable, leak-proof container and closed for transport from the laboratory. Follow local, regional, state, national, and international regulations for waste disposal. State and local waste disposal regulations vary. For more information, see:

• Environmental Protection Agency Regulations
• State Universal Waste Programs in the United States
• U.S. Department of Transportation's: Managing Solid Waste | F-2 pages 94–97

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