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Gary Evans writes Hospital Infection Control & Prevention (HIC), Hospital Employee Health (HEH) and contributes to IRB Advisor (IRB). As senior writer at AHC, Evans has written numerous articles on infectious disease threats to both patients and health care workers, including pandemic influenza, MERS and Ebola. He has been honored for excellence in analytical reporting five times by the National Press Club in Washington, DC.
Of several recent laboratory safety breaches at the Centers for Disease Control and Prevention, the one that hit CDC director Tom Frieden, MD, MPH, the hardest was sending an unsuspecting outside lab some relatively benign influenza samples that had accidently been contaminated by the deadly H5N1 avian flu virus.
The worst case scenario is fairly easy to imagine because H5N1 has a 60% mortality rate in humans. No one was infected, but adding considerable insult to this injury was the disturbing revelation that Frieden was not informed of the incident until some six weeks after it occurred.
"At this point everything we've looked at strongly suggests that there was no exposure of anyone to influenza," Frieden said. "The people who were involved were wearing what are called 'PAPRs' or positive air pressure respirators. They were working in an enhanced BSL-3 facilities [with] multiple redundant checks to prevent infection with flu. As to why it took six weeks for [the incident] to be made apparent to us, I can think of no valid explanation."
To make matters worse the cross contamination of flu strains occurred in the influenza lab, a world class facility that is a point of pride at the CDC.
“For me personally, this is the most distressing of the [recent] incidents for two reasons,” Frieden said at recent press conference. “First, because it happened in our influenza laboratory. And second, because it happened six weeks ago, and I learned about it less than 48 hours ago.”
The cross contamination apparently occurred when the CDC influenza lab was preparing a low-risk strain of animal influenza for shipment to a U.S. Department of Agriculture lab. The lab that received the strain was expecting to be working with low pathogenic flu, but noticed that something was amiss with the isolates. After testing the strain they informed the CDC lab that it was contaminated with H5N1, which was confirmed by the CDC when the specimen was sent back.
“We're still just beginning the investigation to determine how this happened,” Frieden said. “The work was done in one room. So that leads to some early hypotheses of what might have happened. But it's going to take a detailed investigation. And we may not know for certain exactly what happened, but we'll do everything we can to find out.”
In response to the incident, the CDC has placed a moratorium on biological material leaving BSL-3 and BSL-4 laboratories until further notice. “We will assess laboratory by laboratory before reopening,” Frieden said. Though no one was infected at either the CDC or the other lab, the incident was clearly disturbing to Frieden.
“The fact that something like this could happen in such a superb laboratory is unsettling because it tells me that we need to look at our culture of safety throughout all of our laboratories,” he said. “[It is] deeply troubling that there was an unacceptable delay in providing this information. It's very important to have a culture of safety that says if you've got a problem, talk about it. The biggest way to get into more trouble is not to talk about something when you've got a problem."