Vaccinia Virus Biological Agent Reference Sheet (BARS)

This guidance is maintained by Cornell EHS Biosafety and Biosecurity. It is reviewed periodically and may be revised as federal guidance, vaccine recommendations, medical countermeasures, institutional risk tolerance, or proposed research activities change.

Important scope note: This page applies to vaccinia virus (VACV), recombinant vaccinia virus, vaccinia-vectored systems, and other poxvirus vector systems when reviewed by Cornell Biosafety and the Cornell IBC. VSV-G is not vaccinia virus. VSV-G is vesicular stomatitis virus glycoprotein and is most commonly encountered at Cornell as an envelope used to pseudotype lentiviral or retroviral vectors. VSV-G-pseudotyped lentiviral vectors should be reviewed under the applicable lentiviral vector guidance, not this vaccinia page.

Risk group, biosafety level, animal biosafety level, PPE, medical surveillance, vaccination, engineering controls, and operational requirements are determined by Cornell Biosafety and the Cornell IBC through a site-specific and activity-specific risk assessment. Strain, replication competence, inserted gene, route of exposure, viral titer, volume, sharps use, animal work, and personnel risk factors may change the required controls.

Summary

Agent or Vector Type	Risk Group	Biosafety Level	Animal Housing Biosafety Level
Replication-competent vaccinia virus, including recombinant vaccinia derived from replication-competent strains	RG2 starting point; final determination by IBC/EHS risk assessment	BSL-2 minimum; BSL-2 Enhanced or additional controls may be required based on strain, inserted gene, titer, volume, aerosol/splash potential, sharps use, or personnel risk factors	ABSL-2 minimum for infected animals; additional controls may be required based on species, route, dose, shedding, procedures, and facility conditions
Replication-deficient or highly attenuated poxvirus vectors, such as MVA, NYVAC, ALVAC, or TROVAC	Risk assessment required; often lower risk than replication-competent VACV when no helper virus or replication-competent contaminant is present	Containment assigned by IBC/EHS risk assessment; BSL-1 or BSL-2 may be appropriate depending on construct, insert, host range, helper systems, and procedures	Assigned by animal- and activity-specific risk assessment

Agent Characteristics

Agent Type: Virus; recombinant viral vector when genetically modified.

Description: Vaccinia virus (VACV) is a linear, double-stranded DNA virus in the Poxviridae family and Orthopoxvirus genus. It is the live virus used in traditional smallpox vaccines and remains a common laboratory tool and viral vector platform. VACV is related to orthopoxviruses that infect humans, including variola virus, mpox virus, and cowpox virus. VACV strains vary substantially in virulence, replication competence, host range, and risk to laboratory personnel. Non-highly attenuated strains, including New York City Board of Health-derived strains and Western Reserve (WR), can replicate in human cells and can cause laboratory-associated infection. Highly attenuated or host-restricted poxvirus vectors such as Modified Vaccinia Ankara (MVA), NYVAC, ALVAC, and TROVAC are generally lower risk but still require protocol-specific review.

Host Range: Several mammals, including humans and multiple laboratory or agricultural animal species. Host range and shedding depend on strain, construct, route, dose, and host species.

Host Shedding / Infectious Materials: Infectious material may include lesions, lesion fluid, crusts or scabs, contaminated dressings, infected cell cultures, infected animals, animal tissues, bedding, waste, and potentially some clinical specimens. Vaccination-site material from replication-competent vaccinia vaccines can contain infectious vaccinia virus until the lesion resolves and the scab separates.

Routes of Exposure to Humans: Percutaneous injury, contact with broken or abraded skin, mucous membrane exposure, ocular splash, contact with contaminated fomites or infected animals, ingestion, and inhalation of aerosols generated during laboratory procedures.

Infectious Dose: Not precisely established for laboratory exposure. Exposure risk is influenced by strain, titer, volume, route, host susceptibility, vaccination status, and whether the exposure involves sharps, mucous membranes, or broken skin.

Incubation Period: Local lesions after exposure may develop within days to approximately two weeks, depending on route, dose, vaccination status, and host factors.

Health Hazards

Signs and symptoms of vaccinia infection may include:

Localized papule, vesicle, pustule, ulcer, or necrotic lesion at the inoculation or exposure site
Pain, swelling, erythema, cellulitis-like inflammation, or regional lymphadenopathy
Fever, malaise, headache, myalgia, fatigue, or other systemic symptoms
Ocular infection after splash or autoinoculation, which can threaten vision
Progressive, generalized, eczema vaccinatum-like, or severe disease in persons with immunocompromising conditions, certain skin conditions, pregnancy, or other risk factors

Immunizations: Vaccination may be recommended or offered for personnel with occupational exposure risk to orthopoxviruses. ACIP recommends JYNNEOS as an alternative to ACAM2000 for research laboratory personnel, clinical laboratory personnel performing diagnostic testing for orthopoxviruses, designated response team members, and certain health care personnel at risk for occupational exposure. ACAM2000 has also been recommended for laboratory personnel who directly handle cultures or animals contaminated or infected with replication-competent vaccinia virus, recombinant vaccinia viruses derived from replication-competent vaccinia strains, or other orthopoxviruses that infect humans. Vaccination is not generally recommended solely for work with replication-deficient poxvirus strains such as MVA, NYVAC, TROVAC, or ALVAC when those are the only materials handled.

Booster Guidance: Personnel with ongoing occupational exposure risk to less virulent orthopoxviruses such as vaccinia virus or cowpox virus should receive JYNNEOS booster doses at least every 10 years after the primary JYNNEOS series. Personnel with ongoing occupational exposure risk to more virulent orthopoxviruses such as variola virus or mpox virus have shorter booster intervals under ACIP guidance.

Treatment / Medical Countermeasures: There is no routine self-administered post-exposure prophylaxis for laboratory vaccinia exposures. Medical management depends on exposure route, strain, dose, vaccination status, host risk factors, and clinical presentation. Severe vaccinia disease or vaccine-related adverse events may require consultation with public health authorities and CDC. Vaccinia immune globulin intravenous (VIGIV) is recommended as first-line therapy for certain adverse reactions resulting from continued vaccinia virus replication after ACAM2000 or APSV vaccination, and antivirals may be considered after CDC consultation.

Personnel who are pregnant, immunocompromised, have a history of eczema or atopic dermatitis, have active exfoliative or barrier-disrupting skin disease, have household contacts with these conditions, or have other medical concerns should be evaluated through the applicable occupational health process before working with replication-competent vaccinia virus or recombinant vaccinia derived from replication-competent strains.

Agent Viability

Survival Outside Host	Disinfection	Inactivation
Poxviruses are environmentally stable and resistant to drying. Dried VACV has been reported to remain viable for many weeks under cool, low-moisture conditions. Do not rely on drying, elapsed time, or visual cleanliness as a decontamination method.	Use an EPA-registered hospital disinfectant or other disinfectant approved in the MUA/SOP for vaccinia virus or non-enveloped virus/poxvirus applications. Follow the label or approved SOP for dilution, surface compatibility, organic load, wet contact time, safe handling, and disposal. Bleach, aldehydes, peracetic acid, some quaternary ammonium combinations, phenolics, hydrogen peroxide, and iodine compounds have been reported to inactivate VACV under specified conditions, but product selection and contact time must be approved for the work.	Physical or chemical inactivation methods used to reduce containment requirements must be included in the approved MUA and SOPs. VACV has been reported to be inactivated by dry heat at 95°C for 2 hours; moist heat sensitivity depends on conditions and the heat-resistant fraction may require higher temperatures. Inactivation must be verified or otherwise accepted by Cornell Biosafety and the Cornell IBC before material is handled under reduced containment.

For more guidance on disinfection, see: disinfectant selection.

Laboratory Hazards

Sharps injuries, including needles, scalpels, microtome blades, broken glass, and animal-inoculation devices
Mucous membrane or ocular splash during pipetting, vortexing, sonication, centrifugation, animal inoculation, cage changing, or tissue harvest
Contact with broken skin, uncovered wounds, dermatitis, or abraded skin
Aerosol- or droplet-generating activities, including centrifugation, sonication, high-pressure systems, vortexing, tube-cap opening, liquid culture manipulation, and animal procedures
Contaminated equipment, surfaces, gloves, lab coats, animal bedding, or waste
Unclear separation of replication-competent and replication-deficient poxvirus work areas or materials
Inserted genes that may alter host range, virulence, immunomodulation, oncogenicity, tropism, shedding, or environmental stability

Laboratory-Acquired Infection History: Laboratory-associated vaccinia infections are well documented and have occurred through needlestick injuries, ocular exposures, direct contact, and other laboratory exposures. Vaccinated personnel may still experience infection after a high-risk exposure, although vaccination can reduce risk and severity.

Laboratory Handling Guidelines

Laboratory Biosafety Level (BSL): BSL-2 is the minimum starting point for replication-competent vaccinia virus and recombinant vaccinia derived from replication-competent strains. BSL-2 Enhanced or additional controls may be required based on risk assessment. Replication-deficient or highly attenuated poxvirus vectors may be assigned different containment after IBC/EHS review.

Attenuated / Replication-Deficient Poxvirus Systems: MVA, NYVAC, ALVAC, and TROVAC are examples of attenuated or host-restricted poxvirus systems. Western Reserve (WR) is not an attenuated alternative; it should be treated as a non-highly attenuated replication-competent laboratory vaccinia strain unless the submitted construct and strain-specific documentation support a different determination.

Training	Lab Engineering Controls	Personal Protective Equipment
EHS Laboratory Safety Training Biosafety Level 2 Training Lab-specific protocol training for strain, construct, route, titer, waste, spill response, sharps controls, and exposure reporting Bloodborne Pathogens training when the work involves human blood, human-derived materials, OPIM, or other tasks covered by the Exposure Control Plan Shipping training for personnel who package or ship regulated biological materials	Certified Class II Biosafety Cabinet for all manipulations of infectious or potentially infectious vaccinia materials that may generate droplets, aerosols, or splashes Sealed rotors or centrifuge safety cups; load and unload in a BSC when required by risk assessment Sharps reduction and use of safety-engineered sharps whenever feasible Secure primary containers, secondary containment for transport, and decontamination of outer surfaces Dedicated equipment or documented decontamination procedures when shared equipment is used Clear segregation of replication-competent and replication-deficient poxvirus work areas, stocks, waste, and equipment when both are present	Disposable nitrile gloves; double gloves required or recommended for work with replication-competent virus, high-titer stocks, animal work, or spill cleanup Solid-front or snap-front lab coat with tight cuffs; disposable gown or sleeve covers when splash, animal, or high-contamination risk is present Eye protection for routine BSL-2 work; goggles and face shield when splash, spray, or mucous membrane exposure is possible Respiratory protection when aerosol-generating procedures cannot be fully contained in a BSC or when required by risk assessment; personnel using respirators must be enrolled in the respiratory protection program Cover cuts, abrasions, dermatitis, or broken skin before work; personnel with significant skin barrier issues may require medical review before participation

Waste Management: Regulated Medical Waste (RMW), with additional chemical or hazardous waste requirements when disinfectants, fixatives, or extraction reagents create mixed waste concerns.

Shipping Guidance: Refer to EHS Biological Materials Shipping before shipment. Classification depends on material, concentration, replication competence, diagnostic or research use, and applicable DOT/IATA requirements.

Animal Vivarium Guidance

Animal Housing Biosafety Level (ABSL): ABSL-2 is the minimum starting point for animals infected with replication-competent vaccinia virus or recombinant vaccinia derived from replication-competent strains. Additional controls may be required based on species, strain, construct, dose, route, shedding, bedding/cage handling, procedures, personnel exposure potential, and facility design.

Animal Biosecurity: Experimental animals are housed separately and managed according to the approved animal protocol, MUA, facility SOPs, and CARE requirements.

Perform Inoculations: in a certified Biosafety Cabinet (BSC) or other approved primary containment device unless otherwise approved through risk assessment.

Change Cages: in a Biosafety Cabinet (BSC) or other approved containment equipment unless otherwise approved through risk assessment.

Exposure and Spill Procedures

Mucous Membranes / Eyes: Flush eyes, mouth, or nose for 15 minutes at an eyewash station. Report immediately to the supervisor and EHS Biosafety. See: responding to exposures.

Percutaneous, Broken Skin, or Other Skin Exposure: Wash with soap and water for 15 minutes for needlesticks, cuts, open wounds, broken skin, or potentially contaminated skin. Do not scrub aggressively enough to damage skin. Report immediately to the supervisor and EHS Biosafety.

Small Spills: Notify others working in the laboratory. If aerosols may have been generated, leave the area and allow aerosols to settle when safe to do so. Don appropriate PPE. Cover the spill with absorbent material and apply approved disinfectant from the perimeter toward the center. Maintain the required wet contact time from the approved SOP or disinfectant label 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. Incidents involving recombinant or synthetic nucleic acid molecules, genetically modified vaccinia, or recombinant viral vectors may require reporting under Cornell IBC and NIH Guidelines requirements.

Medical Follow-Up:

For students, seek medical attention at Cornell Health or a 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, urgent care, or the medical provider identified in the approved occupational health plan. 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.

ell EHS would like to thank Emory University for using their Biological Agent Reference Sheet (BARS) format and some content.

Guidelines

Biosafety in Microbiological and Biomedical Laboratories (BMBL)

More Information

References:

Primary Biosafety, Occupational Health, and Regulatory Guidance

Orthopoxvirus Vaccination and Medical Countermeasures

Petersen BW, Harms TJ, Reynolds MG, Harrison LH. Use of Vaccinia Virus Smallpox Vaccine in Laboratory and Health Care Personnel at Risk for Occupational Exposure to Orthopoxviruses — Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2015. MMWR Morb Mortal Wkly Rep. 2016;65(10):257-262.
Rao AK, Petersen BW, Whitehill F, Razeq JH, Isaacs SN, Merchlinsky MJ, et al. Use of JYNNEOS (Smallpox and Monkeypox Vaccine, Live, Nonreplicating) for Preexposure Vaccination of Persons at Risk for Occupational Exposure to Orthopoxviruses: Recommendations of the Advisory Committee on Immunization Practices — United States, 2022. MMWR Morb Mortal Wkly Rep. 2022;71(22):734-742.
Centers for Disease Control and Prevention. Smallpox Vaccine Adverse Events.

Vaccinia Laboratory-Acquired Infection and Occupational Exposure Literature

MacNeil A, Reynolds MG, Damon IK. Risks associated with vaccinia virus in the laboratory. Virology. 2009;385(1):1-4. doi:10.1016/j.virol.2008.11.045
Centers for Disease Control and Prevention. Laboratory-Acquired Vaccinia Exposures and Infections — United States, 2005–2007. MMWR Morb Mortal Wkly Rep. 2008;57(15):401-404.
Lewis FMT, Chernak E, Goldman E, Li Y, Karem K, Damon IK, et al. Ocular vaccinia infection in laboratory worker, Philadelphia, 2004. Emerg Infect Dis. 2006;12(1):134-137.
Mempel M, Isa G, Klugbauer N, Meyer H, Wildi G, Ring J, Hofmann H. Laboratory acquired infection with recombinant vaccinia virus containing an immunomodulating construct. J Invest Dermatol. 2003;120(3):356-358. doi:10.1046/j.1523-1747.2003.12074.x
Whitehouse ER, Rao AK, Yu YC, Yu PA, Griffin M, Gorman S, et al. Novel Treatment of a Vaccinia Virus Infection from an Occupational Needlestick — San Diego, California, 2019. MMWR Morb Mortal Wkly Rep. 2019;68(42):943-946.
Isaacs SN. Working Safely with Vaccinia Virus: Laboratory Technique and Review of Published Cases of Accidental Laboratory Infections with Poxviruses. In: Vaccinia Virus: Methods and Protocols. Methods in Molecular Biology. 2019.

Vaccinia Biology, Vectors, Persistence, and Disinfection

Jacobs BL, Langland JO, Kibler KV, Denzler KL, White SD, Holechek SA, et al. Vaccinia virus vaccines: past, present and future. Antiviral Res. 2009;84(1):1-13. doi:10.1016/j.antiviral.2009.06.006
Paoletti E, Taylor J, Meignier B, Meric C, Tartaglia J. Highly attenuated poxvirus vectors: NYVAC, ALVAC and TROVAC. Dev Biol Stand. 1995;84:159-163.
Moss B. Replicating and host-restricted non-replicating vaccinia virus vectors for vaccine development. Dev Biol Stand. 1994;82:55-63.
de Oliveira TM, Rehfeld IS, Coelho Guedes MI, Ferreira JM, Kroon EG, Lobato ZI. Susceptibility of Vaccinia virus to chemical disinfectants. Am J Trop Med Hyg. 2011;85(1):152-157. doi:10.4269/ajtmh.2011.11-0144