He said it remains unclear whether there was live Ebola virus in the specimen. In addition, the technician was not performing a procedure that would elevate the risk of exposure. The specimen was small and the procedure did not include any action that may have dispersed it, Skinner said.
The mistake, which was discovered Tuesday, represents another in a series of lab blunders by the agency this year. No one was injured in those incidents, which involved the mishandling of anthrax and deadly bird flu. But they led CDC Director Tom Frieden to tell Congress this summer that his agency has “an insufficient culture of safety,” even as he promised reforms. The head of the CDC’s anthrax lab soon after resigned.
This latest incident raised new concerns among experts.
“Why did it happen again?” said Dr. Dennis Maki, a University of Wisconsin-Madison infectious disease specialist. He said the CDC had existed for decades with a pristine reputation. “It suggests something has changed in the culture.”
In June, CDC employees failed to completely kill anthrax before sending samples to two other CDC labs with fewer safeguards, potentially exposing dozens of employees to the live pathogen. The CDC’s vaunted influenza lab was thrust into a harsh spotlight when relatively harmless bird flu was accidentally contaminated with a much deadlier strain, and then sent to a lab run by the U.S. Agriculture Department. The incident was discovered in May but not reported to the agency’s top brass until July.
“I am troubled by this incident in our Ebola research laboratory in Atlanta,” Frieden said in a statement Wednesday. “We are monitoring the health of one technician who could possibly have been exposed and I have directed that there be a full review of every aspect of the incident and that CDC take all necessary measures.”
This week’s incident occurred when staff mixed up two sets of samples of the Ebola virus, Reynolds said. One set, in which the virus had been killed, was placed in storage in the high-security BSL-4 lab.
Another set of samples, which may still have contained live virus, was wrongly transferred to the less secure BSL-2 lab, where a technician worked on it, she said. The technician was wearing gloves and a gown but no face shield.
BSL-4 labs contain the highest level of security, in which workers wear full body suits, whereas the BSL-2 lab workers wear gowns, gloves and other equipment.
The samples were secured in such a way as to preclude any contamination during the transfer, Reynolds said. The material was on a sealed plate, but should not have been moved into a less secure lab.
The Ebola research was focused on the virus’s degree of virulence and how long it survives with a person who has died.
Frieden said that in recent months, thousands of laboratory scientists and workers have taken “extraordinary steps” to improve safety.
“No risk to staff is acceptable, and our efforts to improve lab safety are essential — the safety of our employees is our highest priority,” Frieden said.
Since the incident, the BSL-2 lab has been closed, staff notified, and an internal review begun. Regulatory oversight agencies have also been notified, including U.S. Health and Human Services Secretary Sylvia Burwell.
The BSL-2 lab where the potential exposure occurred had already been decontaminated and the material destroyed as a routine procedure before the error was identified. The lab has since been decontaminated for a second time. The transfer of experimental materials from the BSL-4 lab has been stopped while the review takes place, officials said.