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.Learn more from a media statement at the CDC website