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Lentiviral Vectors (1st and 2nd Generation) Biological Agent Reference Sheet (BARS)

Disclaimer: Risk group, biosafety level, and all other precautions noted here are subject to change after a risk assessment by EHS.


Agent Type Risk Group Biosafety Level Animal Housing Biosafety Level
Viral Vector  RG-3 BSL-2 with special practices (BSL-2 Enhanced) ABSL-1, ABSL-2

Agent Characteristics 

Risk Group: RG-3 associated with human disease, rarely serious; preventive, or therapeutic interventions often available.

Agent Type: Viral Vector

Description: Lentiviruses are medium-sized (120 nm), enveloped viruses composed of a nucleocapsid containing two copies of single-stranded positive-sense RNA. Lentivirus is a genus of slow viruses (lente-, Latin for "slow") of the Retroviridae family, characterized by a long incubation period. The viruses are species-specific in host range and several have been recognized as pathogens of domestic animals, non-human primates, and humans. HIV-derived vectors are highly efficient vehicles for in vivo gene delivery. In first and second-generation lentiviral vectors cis and trans-acting factors of the Lentivirus are on separate plasmids depending on the viral vector generation. Third and fourth generation systems are currently the safest to use because the virus production is split across four or more plasmids, decreasing the likelihood of forming a virulent, wildtype virus.

Host Range: The host range is dependent upon the viral envelope glycoproteins and structural proteins involved in integration. Possible hosts include human, murine, feline, bovine, and avian. Pseudotyping lentiviral vectors with Vesicular Stomatitis Virus glycoprotein G (VSV-G) increases the host range to a broad array of cell types and species. Though advantageous for research purposes, this poses an increased risk of infection in case of exposure to VSV-G pseudotyped lentiviral vectors for lab workers, since these vectors will be able to target a larger range of cells

If an exposure occurs, seek treatment with a medical professional within 4 hours and no later than 72 hours.

Host Shedding : Unknown                             Routes of Exposure to Humans: Mucous Membranes, Contaminated Items, Percutaneous, Sexual, Broken skin

Infectious Dose: Unknown                              Incubation Period: 1-6 months

Health Hazards

Lentiviruses may persist lifelong due to their ability to integrate into the host chromosome and ability to evade host immunity. Signs and symptoms of infection may include:

  • Flu-like symptoms (i.e. fever, headache, dehydration, weight loss, lethargy)

  • Gastrointestinal symptoms (i.e. loss of appetite, nausea, vomiting, diarrhea)
  • Neurological symptoms (i.e. loss of sensation, ataxia)
  • Lymphoreticular symptoms (i.e. enlarged internal organs or lymph nodes)
  • Reproductive Health concerns (i.e. abortion, fetal abnormalities)

Immunizations: None available                            

Prophylaxis*: Post-exposure prophylaxis for occupational exposure with HIV-based viral vectors may include the use of antiretroviral drugs. If an exposure occurs, seek treatment with a medical professional within 4 hours and no later than 72 hours.

*Formal medical advice is obtained during medical consultations with Cornell Health or primary healthcare provider as needed.

Agent Viability 

Survival Outside Host

Disinfection Inactivation

90-99% reduction in several hours

1:10 Bleach Dilution (30+ seconds) or other EHS-approved disinfectant.

  • Heat at 56°C for 30+ minutes

For more guidance on disinfection see: disinfectant selection.

Laboratory Hazards 

Risks include direct contact with skin and mucous membranes of the eye, nose and mouth, parenteral inoculation, ingestion.

  • High energy-creating activities (centrifugation, sonication, high-pressure systems, vortexing, tube cap popping)

  • Handling of sharps (needles, scalpels, microtome blades, broken glass, etc.)
  • Splash/droplet-creating activities (shaking incubators, liquid culturing, mechanical pipetting)
  • Equipment contamination
  • Exposed skin/uncovered wounds/broken or chapped skin

Laboratory Acquired Infection (LAI) History: None known.

Laboratory Handling Guidelines 

Laboratory Biosafety Level (BSL): BSL-2 with special practices for all first and second-generation lentiviral vectors.

Attenuated Strain Alternatives: Use of 3rd or 4th generation Lentiviral vectors is recommended where possible. 


Lab Engineering Controls Personal Protective Equipment
  • Eye Protection
  • Double gloves, disposing of outer pair in BSC every time the researcher exits the BSC
  • Disposable solid front gown
  • Additional mucous membrane protection - disposable medical mask when working in BSC; N95 respirator outside containment*

*Respirators require medical consultation and users must take EHS 2381 - Respiratory Protection.

Waste Management: Regulated Medical Waste (RMW)

Shipping Guidance: Refer to EHS Biological Materials Shipping 

Animal Vivarium Guidance

Animal Housing Biosafety Level (ABSL): ABSL-2
Infected animals can excrete lentivirus, so cages and bedding are considered biohazardous for a minimum of 72 hours, so all animals that receive lentivirus at Cornell are handled as ABSL-2 for 7 days. After 7 days and a subsequent cage change animals may be moved to ABSL-1, depending on the risk assessment recorded in the IACUC protocol. Take precautions to avoid creating aerosols when emptying animal waste material. Soiled cages are disinfected prior to washing.

Animal Biosecurity: Experimental animals are housed separately

Perform Inoculations: In a Biosafety Cabinet

Change Cages: In a Biosafety Cabinet

Exposure and Spill Procedures

Mucous Membranes: Flush eyes, mouth, or nose for 15 minutes at an eyewash station. See: responding to exposures.

Other Exposures: Wash with soap and water for 15 minutes (open wounds, sores, etc.) or a minimum of 20 seconds for areas with intact skin. See: responding to exposures.

Small Spills: Notify others working in the lab. Evacuate the area and allow 30 minutes for aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply disinfectant, working from the perimeter toward the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials. See spill cleanup.

Large Spills: Request assistance from the EHS Spill Team by calling CUPD dispatch. Call 911 from a campus phone or 607-255-1111 from a mobile phone.

Incident Reporting: Immediately report the incident to the supervisor and complete the EHS online injury/illness report as soon as possible.

Medical Follow-Up:
Seek consultation with a medical professional within 4 hours and no later than 72 hours.

  • For students, seek medical attention at Cornell Health or local primary care provider. Call Cornell Health at 607-255-5155 (24-hour phone consultation line) or a local urgent care. 

  • For faculty and staff, seek medical evaluation with a local primary care provider or urgent care. Cornell Health does not see employees for post-exposure care. 
  • Emergencies: Call 911 from a campus phone or 607-255-1111 from a mobile phone. 

More Information


  1. CDC. 2009. Biosafety in Microbiological and Biomedical Laboratories. Center for Disease Control and Prevention.
  2. NIH Biosafety Considerations for Research with Lentiviral Vectors