Thursday, February 05, 2015

CDC Report On Investigation Into December’s Ebola Lab Incident





# 9675


All in all, 2014 will go down as a difficult year for CDC labs, with several high profile lab biosafety incidents involving `select agents’, including H5N1 and anthrax last summer (see CDC Announces Another Serious Biosecurity Incident, and Ebola in December (see CDC Reports Potential Ebola Exposure At Lab).


`Select agents’ are those  pathogens that have been deemed to pose a significant biological hazard, and among those, Tier 1 select agents are considered `biological agents and toxins present the greatest risk of deliberate misuse with significant potential for mass casualties or devastating effect to the economy, critical infrastructure, or public confidence, and pose a severe threat to public health and safety:’

While obviously of concern, in all of these incidents the biohazard was contained, and no one ended up being infected. In August, in CDC H5N1 Incident & Lab Safety Progress Reports, we looked at some of the steps being taken by the CDC to increase lab safety and foster a greater `culture of safety’.


But, as we learned on Christmas Eve (see CDC Statement On Ebola Lab Incident), whenever you mix complex systems with human foibles, errors can still occur.  Even in the best of labs.

Last night the CDC released the following report on that incident:


CDC Releases Report on Recent Lab Incident

CDC review shows unlikely exposure, makes recommendations for continued safety improvements

For Immediate Release: Wednesday, February 4, 2015
Media Relations, Office of Communication
(404) 639-3286

The Centers for Disease Control and Prevention (CDC) has completed an internal investigation of an incident that occurred in December within the agency’s Ebola virus laboratory, which resulted in no illness and was unlikely to have involved an exposure to live Ebola virus.  CDC’s investigation found that this laboratory incident occurred for two main reasons related to inadequate safeguards: 1) lack of a written study plan that had been approved by a supervisor; and 2) a study plan workflow that was not designed to sufficiently minimize the possibility that human error could result in potential exposure. CDC had already taken many steps to improve safety and will take additional steps as a result of this review. 

In December, CDC reported that a small amount of material from an experiment that was part of an Ebola virus study was securely transported from a select‐agent‐approved BSL‐4 lab to a select‐agent‐approved BSL‐2 lab and may have contained live virus. The material mistakenly transferred during procedures for this study was on a sealed plate but should not have been moved from the BSL-4 laboratory into the BSL‐2 laboratory.  The study involved scientists placing identical oral swab samples from guinea pigs into two sets of tubes—one set of tubes for live virus studies and one set of tubes for studies with inactivated material.  The tubes were identical in brand and size and only differentiated by color caps and labels. Appropriate and approved inactivation procedures, consistent with recently implemented laboratory safety improvements, were used. Unfortunately, however, human error resulted in the swabs being placed into tubes in such a way that another technician mistakenly transported the wrong specimens to the BSL-2 lab.

The report also describes two previous recommendations that had not yet been fully implemented in this lab that could potentially have reduced the likelihood of this incident:  1) installation of a camera system for secondary verification of critical safety control points; and 2) proper use of a required Material Transfer Certificate (MTC) form for materials taken out of CDC’s high containment laboratories to lower biosafety level laboratories, including internal transfers.

CDC’s investigation found that immediate steps were taken to minimize any risk to CDC lab staff and that this incident was reported to appropriate authorities in a timely manner.  In addition, the involved BSL-4 lab has suspended transfers out of the lab until a full review of the incident is completed and appropriate improvements are initiated. CDC is currently installing camera systems in the BSL-4 laboratory and providing clear instructions on the intended use of the MTC form prior to resuming full BSL-4 operations.

The laboratory technician who worked directly with the specimens in the BSL-2 laboratory completed 21 days of direct active monitoring and reported no illness consistent with Ebola.  The agency performed additional laboratory studies on swabs taken the workdays before and after the incident which found it was unlikely that the specimens transferred to the BSL-2 laboratory contained live Ebola virus.  Although the studies determined there was no safety risk to CDC staff or the public, CDC will ensure continuous improvements occur to protect the safety of CDC staff and the broader community.

Among steps CDC is taking or has taken to address this incident:

  • Enhance standard operating procedures for materials intended for inactivation and removal from laboratories to ensure that
    • All materials are in standard, appropriately labeled, easily distinguishable tubes. 
    • Multiple, redundant visual safeguards are used.
  • Ensure CDC scientists have a full understanding of previously recommended laboratory safety improvements, including required use of the MTC form, and that they implement them.
  • Work with CDC scientists from high containment laboratories to establish a peer-review system of written research plans to foster critical thinking on how to optimize workflows in protocols and minimize error.

While the incident described in this report highlights the need for continued enhancements to laboratory safety practices across the agency, CDC has made progress in this area over the past several months. Examples include:

  • Established and recruiting for a new position, the Associate Director for Laboratory Science and Safety, with responsibility for providing agency-wide leadership and accountability for laboratory science, safety, and quality. 
  • Worked with laboratory staff and laboratory leadership to identify other safety improvement measures, including expansion of biosafety training and improvements in research standards and protocols. 
  • Undertaken an inventory of all stored biologic materials.
  • Formed an external laboratory safety working group, under the Advisory Committee to the Director, composed of experts in biosafety and related areas to review and provide input into corrective actions and safeguards across all CDC laboratories.

CDC leaders have expressed their disappointment and have repeatedly stressed the importance of minimizing any potential risk to staff.  CDC’s efforts to improve lab safety are essential—with the safety of employees as the highest priority.  The expertise and world-class knowledge that CDC scientists bring to laboratory work is vital and, while lab work will always carry some risk, it is crucial to saving lives and preventing disease.  CDC is committed to ongoing efforts to identify and implement systems and procedures that will allow the agency to provide maximum protections for laboratory staff and the broader community while conducting its critical laboratory work.

Please see CDC’s laboratory safety site for the full report


Although the CDC’s labs are undoubtedly among the safest in the world, these and other high profile lab incidents (see FDA Statement On Additional 300 Vials Discovered At NIH Campus Lab) have led to numerous calls for greater oversight on the use of select agents, and some restrictions on the type of research that should be permitted. 


The Journal Nature Weighs In On Lab Accidents & Biosafety Making Viruses Deadlier – An Accident Waiting To Happen.


While scientists engaged in this type of work insist that the risks are negligible (see Scientists For Science: GOF Research `Essential’ & Can be Done `Safely’), many others  (see Updating The Cambridge Working Group) are less convinced.

Some earlier blogs on this highly contentious debate include:


mBio: The Risks & Benefits Of `GOF’ Experimentation On Pathogens With Pandemic Potential

The Laboratory Bio-Safety Backlash Continues

ECDC Comment On Gain Of Function Research

Lipsitch & Galvani: GOF Research Concerns

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