The US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, has taken its first disciplinary steps in response to a laboratory mix-up that potentially exposed dozens of employees to anthrax earlier this month.
The agency reassigned the head of the Bioterror Rapid Response and Advanced Technology Laboratory, which was involved with the incident, pending completion of the investigation. An agency spokesperson would not confirm the employee’s name.
The agency says that it still does not know why the lab failed to follow a simple protocol that would have killed the bacteria. According to CDC statements, between 6 June and 13 June, workers at the lab inadvertently shipped live Bacillus anthracis to another CDC lab that was not equipped to handle live bacteria.
According to CDC spokesman Thomas Skinner, the researchers were using a new protocol for the first time. Rather than irradiating the bacteria, which is the more common way of killing them, the researchers were treating them with a series of chemicals and then incubating them for 48 hours to ensure the bacteria were no longer alive. But the workers waited only 24 hours before sending the bacteria off, and the lab that received them did not verify that the bacteria were dead before starting to work with them. Researchers discovered the oversight a week later when they found bacteria growing on a dish.
Skinner says that the CDC is still investigating questions such as why researchers followed the protocol improperly and why the staff did not wait the full 48 hours. On 20 June, the US Department of Agriculture took over the investigation to avoid conflicts of interest.
Although initial reports said that 75 people were potentially exposed, Skinner says that the agency is no longer attempting to estimate an exact number. But he says that more than 70 people have been treated with antibiotics, and some of those have also been vaccinated. The CDC believes that only about seven people had direct contact with the bacteria and are hence at high risk of exposure.
Because the workers were treated quickly, the chances of a worker actually contracting the disease are slim, says Amesh Adalja, a biosecurity expert at the University of Pittsburgh Medical Center’s Center for Health Security in Baltimore, Maryland.
The greater concern, he says, is the failure to follow proper biosafety procedures. “The work they do on anthrax is important, and you don’t want to set back public confidence so people question whether this research needs to be done,” he says.
Richard Ebright, a molecular biologist and biosecurity expert at Rutgers University in Piscataway, New Jersey, says that the incident is the latest in a series of biosecurity failures at CDC labs and the labs the CDC certifies, including a nearly identical event at a California lab in 2004 in which 12 people may have been exposed to anthrax. “The fact that CDC is reprising this ten years later shows they’ve learned nothing,” he says. “Changing one person doesn’t solve problems there.” The agency, he says, needs to undertake a close reassessment of safety training and management.