Biosafety Level Guidance for COVID-19 Research

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Written by: Scott Mechler

BS Mechanical Engineering, Mechanical Engineer

What biosafety level is required to handle samples and/or perform research containing the SARS-CoV-2 virus?  Read on for the latest recommendations from the Centers for Disease Control (CDC).


A Biological Safety Level (BSL 1, 2, 3, or 4) is assigned to a biological lab as a safeguard to protect laboratory personnel, as well as the surrounding environment and community.

With research into potential treatments, therapies and vaccines for the SARS-CoV-2 virus (known widely as the COVID-19 Coronavirus) exploding across the globe, many institutions and laboratories are wondering whether their equipment and lab are considered safe to contain samples of the virus. As discussed in our previous blog on biosafety levels, airborne transmissible diseases like COVID-19 are typically categorized as Biosafety Level 3 (BSL-3).  BSL-3 laboratories are almost always purpose-constructed containment laboratories, outfitted with specialized equipment and HVAC systems designed to ensure no airborne particles can exit the contained space.

Current Guidance

The CDC has recently outlined biosafety guidelines specific to SARS-CoV-2 isolates or cultures, recommending that virus isolation and characterization of viral agents from SAR-CoV-2 specimens must be processed within a BSL-3 laboratory space using BSL-3 procedures. However, they have also recommended that a BSL-2 laboratory may perform routine diagnostic testing (refer to CDC for list of tests) of specimens using Standard Precautions. Further, CDC recommends procedures like virus concentration, precipitation or filtration may be performed in a unidirectional air-flow BSL-2 provided certain BSL-3 precautions and procedures are followed.

Recommendations provided by the World Health Organization (WHO) are largely in line with the CDC’s Guidance. It is important to note that this new WHO document, released March 18 2020, provides updated recommendations as compared to the often referenced, but now older, WHO recommendations published February 12 2020.

Risk assessments are crucial when determining the required bio-safety level as well as other handling and PPE procedures. Unfortunately, as of the date of this writing, NIH has not classified SARS-CoV-2 into a specific Risk Group. However, NIH has classified SARS-CoV-1 as Risk Group 3.

The International Society for Advancement of Cytometry or ISAC has released specific sorting protocols for diagnostic procedures, publishing these standard operating procedures online.

Laboratory employees working with suspected coronavirus samples within BSL-2 environments should adhere to strict aerosol transmission prevention measures, such as:

  • Tyvek full body suit and gloves, HEPA filtered powered air-purifying respirator
  • Perform all sorting and diagnostics within operational HEPA filtered aerosol management system
  • Wipe down all surfaces before and after sorting and diagnostic procedures with 70% ethanol or 10% hypochlorite
  • Operate only within a facility with negative relative air pressure with respect to surrounding spaces with exhaust air vented directly to the outside rather than recirculating to other spaces
  • Written record of containment measurement and safety checklist

The American Biological Safety Association (ABSA) has published a useful reference chart explaining the CDC & WHO guidance by categorizing specific laboratory procedures and the appropriate BSL requirements. Further the ABSA document discusses practices and techniques, PPE as well as suggested administrative controls.

For additional biosafety level guidance for COVID-19, contact Consolidated Sterilizer Systems today.

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