SARS-CoV-2 Biological Agent Reference Sheet and Laboratory Guidance

Published: 4/30/2020 Updated: 7/13/2020; 9/03/2020; 10/12/2020; 1/13/2022; 12/4/2023; 8/26/2024

Check back periodically for updates as more information becomes available.

Summary

Agent Characteristics

Description: SARS-CoV-2 may also be called 2019-nCoV, HCoV-19, and COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a member of the Coronaviridae family and genus beta coronavirus that causes COVID-19 infections in humans. Coronaviruses are enveloped viruses that contain a single strand of positive-sense RNA. SARS-CoV-2 is a newly emergent virus first reported as pneumonia of unknown etiology in Wuhan, China in late 2019. Viruses within this family that cause human disease include types 229E, NL63, OC43, and HKU1, which usually cause mild to moderate respiratory tract illness, as well as SARS-CoV and MERS-CoV, which can cause much more severe disease.

Host Range: Humans, ferrets, cats, dogs, mink, and primates

Host Shedding:

• Direct contact
• Feces
• Saliva
• Respiratory droplets

Routes of Exposure to Humans: The primary transmission of SARS-CoV-2 is through close-contact, person-to-person spread. Transmission is driven by respiratory droplets. This mirrors what is known about similar coronaviruses like SARS-CoV and MERS-CoV. Fomite transmission is also a component in the spread of SARS-CoV-2: a person may sneeze or cough onto a surface, leaving potentially infectious material. Subsequent contact with mucous membranes may lead to infection. The role that airborne transmission plays is less clear. Currently, the reproduction number for SARS-CoV-2 infection (R0 ≈ 2.5 for ancestral SARS-CoV-2, Delta variant R0 ≈ 5.08, and R0 estimated to be 3.19 to 3.3 times higher for Omicron) is lower than that for measles, known to spread via aerosols (R0 ≈ 18).

• Aerosol/inhalation
• Direct contact
• Mucous membranes
• Contaminated items

Infectious Dose: Estimated as low as 100 particles

Incubation Period: 2-14 days

Health Hazards

Signs and Symptoms: Symptoms may appear between 2-14 days after exposure to the virus.

• Fever or chills
• Cough
• Shortness of breath or difficulty breathing
• Fatigue
• Muscle or body aches
• Headache
• New loss of taste or smell
• Sore throat
• Congestion or runny nose
• Nausea or vomiting
• Diarrhea

Immunizations: Available - three approved and authorized vaccines in the US

Prophylaxis: None available

Agent Viability

Several research studies have demonstrated the interdependence between the survival of SARS-CoV-2, surface or material composition, temperature, and relative humidity. See the references for more information.

Laboratory Hazards

• High-energy-creating activities (centrifugation, sonication, high-pressure systems, vortexing, tube cap popping)
• Splash/droplet-creating activities (shaking incubators, liquid culturing, mechanical pipetting)
• Equipment contamination
• Exposed skin/uncovered wounds

Laboratory Acquired Infections: 4 confirmed cases

Laboratory Handling Guidance

Labs handling clinical samples will establish a protocol requiring each researcher to take their temperature twice daily and log the information. If the researcher notices that their temperature exceeds 100.4°F, they will contact an appropriate health provider and leave the lab.

Inactivation

All labs working with the inactivated virus are expected to describe the inactivation protocol in their application to the IBC. All inactivation methods must be verified within the lab performing the method after IBC approval. Data from the verification will be made available to EHS Biosafety and the Cornell IBC Chairs for review before work with inactivated materials may proceed.

Samples for RNA extraction are collected in storage buffers designed to inactivate proteins and preserve the RNA. These buffers often contain detergents, such as SDS, which should inactivate an enveloped virus. Data is still being developed and changes frequently. Use universal precautions for handling SARS-CoV-2 samples in storage buffers. However, inactivation by Trizol has been evaluated for the inactivation of MERS-CoV, SARS-CoV, and SARS-CoV-2. When the manufacturer’s instructions are followed, there was no evidence of infectious virus when the results of that lysis were diluted to remove cytotoxic chemicals and added to growing cells. Labs will not be asked to validate this method.

Buffers AVL, ATL, and VXL (all from Qiagen) have been tested with SARS-CoV-2. Both buffer ATL and VXL were capable of inactivating the virus with and without BSA added to the solution. Buffer AVL required modification of the manufacturer's protocol. Labs using buffer AVL will be asked to validate this method.
Heat inactivation has been successful for various sample types that contain SARS-CoV-2. For example, BEI Resources distributes the virus, which has been inactivated using SARS-CoV-2, by heating at 65°C for 30 minutes. Thirty minutes is conservative, based on prior research on the related virus, SARS-CoV, and has been adopted. Inactivation for an hour at 58°C has been shown to achieve the same results and is also acceptable.

Chemical fixation has focused on monolayers of cells and commonly uses 10% neutral buffered formalin, 4% paraformaldehyde, and 1:1 methanol: acetone. Thirty minutes was sufficient to inactivate MERS, but little is known about SARS-CoV-2. The CDC Interim Guidance on Collection and Submission of Postmortem Specimens from Deceased Persons with Known or Suspected COVID-19 instructs that a tissue sample of 4-5 mm in thickness should be placed in at least 10 times the volume of 10% formalin and incubated for 72 hours for optimal fixation. Note: Paraffin-embedded samples will be fully heat-inactivated because the paraffin infiltration step places the sample at a temperature of 60-65°C for around 2 hours.

All inactivation methods used need to be included in the submitted MUA and written standard operating procedures (SOPs).

• Personnel must demonstrate proficiency in carrying out the procedure successfully and as written; this proficiency should be documented by the designated principal investigator.
  • If the lab wishes to use a technique other than the accepted methods described above, they must validate the method before use.
• Any inactivation procedure that requires opening the sample container or has the potential for aerosol creation should take place inside a biosafety cabinet.
• Before any changes to inactivation methods, a new or updated SOP needs to be submitted to EHS Biosafety for risk assessment.

Training

For BSL-2 and BSL-2 Enhanced Work

• EHS Laboratory Safety Training (Workday Learning #2555)
• Lab-specific protocol training

For BSL-3

• BSL-3 training and demonstration of proficiency

Lab Engineering Controls

For BSL-2 and Enhanced BSL-2

• Class II Biosafety Cabinet (BSC)
• Centrifuge lids or safety cups or samples are loaded/unloaded inside the BSC
• Use of screw-top cap tubes in place of snap-cap Eppendorf tubes to minimize aerosol generation and create better primary containment
• Aerosol-resistant pipette tips

For more information about engineering controls in a BSL-3 lab, review the BSL-3 Program Manual.

Personal Protective Equipment

BSL-2 Lab, where aerosol-generating activities can be contained within a BSC or other primary containment device

• Gloves (double gloves recommended)
• Front-close lab coat
• Safety glasses

BSL-2 Enhanced Conditions

• Double gloves. Note: When coming out of a biosafety cabinet, outer gloves are disposed of in biohazard trash within the cabinet.
• Closed-front lab coat
• Face shield
• Respiratory protection, such as N95, is worn where aerosol-generating activities cannot be contained within a BSC or other primary containment device (e.g., spill cleanup). Personnel wearing an N95 for these purposes must be part of the respiratory protection program.

In a BSL-3 Lab

• Powered Air-Purifying Respirator (PAPR)
• Disposable solid-front gown
• Lab-specific scrubs

Waste Management: Regulated Medical Waste (RMW)

Shipping Guidance: review EHS Biological Substances Shipping

Animal Vivarium Guidance

Animal Housing Biosafety Level: ABSL-3

Animal Biosecurity: Experimental animals are housed separately

Perform Inoculations: in Biosafety Cabinet (BSC)

Change Cages: in Biosafety Cabinet (BSC)

Exposure and Spill Procedures

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

Small Spills: Notify others working in the lab. Don appropriate PPE. For spills involving fecal material, cover the area of the spill with paper towels, work from the perimeter toward the center, and use the paper towels to remove the spill and associated organic material. Discard contaminated paper towels. For spills involving fecal material and all other spills, apply (or re-apply) 6% hydrogen peroxide on the spill site. Allow 20 minutes of contact time. After 20 minutes, use paper towels to remove the 6% hydrogen peroxide. See: Responding to a Biological Spill.

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:

• 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 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.