The Centers for Disease Control and Prevention has reassigned the director of the bioterror lab that experienced a potential anthrax exposure.
Dozens of CDC scientists and other workers are now taking antibiotics and anxiously watching for any signs of disease, even though the agency issued a statement saying the risk of infection is "very low."
A team of investigators from the Federal Select Agent Program, which polices labs working with potential bioterror germs, was expected to arrive at the CDC's Atlanta headquarters today or tomorrow, CDC spokesman Tom Skinner said Monday. Their investigation and an internal CDC inquiry seek to find out how one of the world's premier public health laboratories mistakenly sent live samples of the particularly deadly Ames strain of anthrax to other agency labs, where workers believed the bacteria had been deactivated.
The CDC said Thursday that it may take disciplinary action against any employee whose failure to follow biosafety protocols led to the potential exposure of more than 80 employees to the deadly microbe.
Skinner said the head of the CDC's Bioterror Rapid Response and Advanced Technology Laboratory had been "detailed to another job" pending completion of the agency's review, but he said he could not confirm the employee's name. Reuters, citing two CDC scientists who are not authorized to speak to the press, identified the employee is Michael Farrell.
Even with antibiotic treatment, anthrax has a fatality rate of 28% to 45%, depending on the type of exposure, according to information on the CDC's website. It can take weeks or even months for symptoms to develop.
"There are a lot of people going through a lot of unnecessary anxious moments," Skinner said. "Things like this shouldn't happen. These are 'never' events. They should never happen. Period."
Most of the staffers who are counted among possible exposures are scientists, lab technicians, administrative and maintenance staff who may have passed through areas where the live anthrax samples were handled without proper protective equipment and barriers, Skinner said.
About seven CDC scientists are at heightened risk because they had more direct exposure, he said. They would most likely have been vaccinated against anthrax previously because of their jobs. Now they're taking antibiotics and would have been offered a booster vaccine, he said.
Some of this small group of scientists were involved in agitating or shaking test tubes of what they thought were deactivated anthrax spores, then lifting the tops off the tubes. That may have aerosolized the spores, creating the risk that these scientists inhaled some of the anthrax.
When working with live anthrax, scientists work in Biosafety Level 3 labs with safety equipment to prevent exposure. Live anthrax is supposed to be handled under negative air pressure in a special safety cabinet, and scientists wear personal breathing equipment.
But in the recent incident, because the scientists thought the spores were deactivated, the test tubes were opened in two Biosafety Level 2 labs with minimal protections, Skinner said. The scientists might have been wearing gloves, gowns and goggles, but they would not have been using a safety cabinet or a personal air supply.
For more than 50 employees who are on a 60-day course of antibiotics, it is not possible for blood tests to identify antibodies that would show exposure to the bacteria, Skinner said. Active disease would be diagnosed through symptoms and chest X-rays, he said.
The series of mistakes happened between June 6 and June 13.
The problem began when scientists in one of the CDC's Biosafety Level 3 labs were preparing samples of anthrax for use in research on ways to detect dangerous pathogens, the CDC has said The scientists grew anthrax bacteria and then used chemicals that were supposed to deactivate the spores.
Before they sent test tubes with deactivated anthrax samples to the other CDC labs, Skinner said, they were supposed to wait 48 hours to see if there was any growth of anthrax in the samples, but they waited only 24 hours. After seeing no growth of the bacteria, they forwarded the samples to the other two CDC labs.
About a week later, when the first group of scientists were preparing to destroy the initial samples, they noticed anthrax bacteria growing, Skinner said.
Skinner said the labs where the possible exposures occurred were decontaminated last week. "We've done some environmental testing in the labs and so far the samples are negative," he said.
The anthrax incident is the latest in a series of safety and security failures at CDC labs that work with dangerous pathogens. They include failures of airflow systems designed to prevent the release of infectious agents and failure to ensure that those working with bioterror agents have proper training, USA TODAY has reported.