Centrifuge Accident Aerosolizes Genetically Engineered Influenza
The postdoc was working alone in a beefed-up BSL-3 laboratory wearing a full lab suit. A respirator system provided oxygen through an air hose. The high-tech safety measures were in place because the viruses in the lab were not your average flu. They were something much more dangerous. They were genetically engineered influenza strains that mixed and matched genes of the common human H3N2 influenza and those of deadly H5N1 "Bird Flu". The kind of unpredictable reassorted flu strain that public health officials fear could cause the next human pandemic.
In the BSL-3 lab, a quantity of the engineered influenza was ready for work. It had been grown mixed with cells. The experiments required purified virus. So, a little after 2:00PM, the researcher transferred a quantity of the virus mixture into a tube. The tube was capped and placed in a centrifuge on a lab bench. The centrifuge would separate out the virus through spinning - centrifugal force.
But the tube was of the wrong type for the centrifuge. There were two almost identical centrifuges in the lab, and their non-interchangeable parts had become mixed up.
The postdoc pushed a button and the centrifuge began to spin. Because the tube was the wrong type, its cap didn't fit correctly. It cracked. The centrifuge lost balance. Turning the machine off, the postdoc observed that the level of virus fluid in the tube had gone down and that its exterior had become wet, both indicators of a leak. This was a serious problem because as the machine spun around, the leaked virus had become aerosolized, at least within the centrifuge.
The Inevitable Human Error
The problem was then compounded by human error, an ever-present factor in lab work. Rather than waiting for the aerosolized flu to settle, the centrifuge was immediately opened. In an invisible puff of air, virus particles wafted out of the machine. Now, the virus was floating around the whole lab, stirred by air movements, then slowing settling on exposed surfaces or being sucked out the exhaust which, hopefully, had effective HEPA filtration (the UT documents are silent on this item).
It was something like a Bird Flu victim walking into the room and coughing all around, spreading virus where he went. Except this mixed up lab creation of H5N1 virus was possibly more efficient at infecting humans than natural "Bird Flu" because of its H3N2 human influenza parts.
The researcher sprayed Lysol and wiped up surfaces in the work area, exited the lab, took a shower, and put on new clothes. Within hours, the postdoc was taking Tamiflu, in the hope that it would stop the virus if the researcher had been infected. For several uncomfortable days, the University of Texas staff waited to see if the researcher developed symptoms. None are reported to have appeared.
The University of Texas at Austin had dodged a bullet. It took longer for a UT biosafety team to straighten out the lab and reopen it. Under any of a variety of plausible scenarios, the accident might resulted in disaster. For example, if the cap leaked but didn't crack, without the postdoc noticing, thereby multiplying the danger to include everyone working in the lab over a longer time.
UT's Bird Flu Hybrid and Deceptive Records
Reading UT's records, it is clear that the University was thinking in terms of public relations from practically the moment that the accident occurred. UT records unscientifically discuss (downplay) the risks and neglect to precisely describe the flu strain. For example, they state that the virus should be considered like far less dangerous H3N2 despite it being a hybrid with "some genes from H5N1". This is deceptive, because the bug that causes flu is composed of only 8 short pieces of RNA that collectively encode just 11 proteins.
Assuming "some genes from H5N1" means at least three RNA pieces or more, or the RNA to encode three proteins, UT's hybrid Bird Flu virus would be about 25% H5N1 (somewhere between 3/11ths and 3/8ths), and potentially much more if the "some genes" were larger ones. That's certainly enough H5N1 genetic material to create an unpredictable and potentially extremely dangerous (pandemic) reassortant. Tiny differences in genes can make huge differences in the bug. Nobody knows for sure how dangerous UT's flu was because, by good fortune, this story doesn't end in human infection.
UT's report also deceptively states "CDC recommends BSL2 practices for H3N2, but it was decided that BSL3 would be prudent for use with this agent," as if UT was acting with an abundance of caution. But UT was was working with a potentially pandemic combination of H5N1 and H3N2. And well before April 2006, there had been scientific discussion and government recommendations made about the need for BSL-3 or higher containment for flu viruses like UT's. Thus, contrary to the implication of its PR-wise assertions, UT was not taking any major steps above and beyond the basic measures that should have been used for such a virus.
Echoes of 2005's Flu Accident
It must have weighed heavily on the minds of University of Texas public relations officials (who were called than 2 hours after the accident) that one year before, on 12 April 2005, global headlines were dominated by the story of Meridian Biosciences Inc., which sent 3,700 samples of potentially dangerous noncontemporary H2N2 flu to labs in the US and across the world. If the UT accident became public at that time, its occurrence on the anniversary of the Meridian story might have cast an extra bright and unflattering light on the University of Texas, potentially unsettling the Molecular Biology Building's many neighbors, many of whom would be unhappy to learn that they came too close for comfort to being ground zero of a deadly flu pandemic.
Need for Federal Reporting
Although it would serve public health and accountability ends, perhaps it is presently optimistic to expect a university to quickly issue bad news about itself, especially when that bad news evokes images of it authoring a public health disaster. But it must be expected that such accidents definitely will be reported to the federal officials that oversee lab safety so that, at least, other labs can learn from the mistake and, for example, not put two identical centrifuges whose parts are NOT interchangeable in the same lab. And so that federal safety officials and funders could examine the accident and impose penalties if institutional safety deficiencies are identified.
Accident, Revised Out of Existence
But it does not appear that anybody outside UT found out about the incident until the Sunshine Project requested the accident report. UT fought to keep it under wraps. While the Texas Attorney General's office was weighing a UT petition to keep the accident details secret, somebody got cold feet. A UT official left two messages on the Sunshine Project answering machine offering to explain what happened, if the Public Information Act request was withdrawn. (We did not respond.)
The Public Information Act request revealed that UT never finalized its accident report and it did not inform NIH. Instead, it made the accident disappear.
How? On the morning after, officials interviewed the postdoc. Remarkably, they recorded that the postdoc's account of the accident had dramatically changed overnight. UT's Environmental Health and Safety Office writes "The researcher thought that the volume of the tube had changed, but was not 100% sure of the original volume." The liquid on the exterior of the tube? It "may have been from condensation". The lid? It, at least, was still broken.
The accident was miraculously converted into a figment of the postdoc's imagination. Pondering the possibility of being at the center of an embarrassing incident that might impair funding and anger UT leaders, was there pressure to change the story? The postdoc knows for certain; but in the absence of any enforced reporting requirements, there were precious few incentives to move forward with accident reporting. Or perhaps UT management insisted that nothing happened unless the Tamiflu-taking postdoc affirmed absolute certainty of details remembered while in the midst of scrambling to contain a potentially life-threatening accident?
Certainly, UT management seized upon the (reported) "not 100% sure" statement. On that basis UT decided that an accident had not occurred. The following gem of illogic (read carefully) provides the University's reasoning that the accident didn't happen: "There is the possibility that there was no leak and therefore no contamination occurred."
The following Monday (17 April), UT's Institutional Biosafety Committee (IBC) held a previously scheduled meeting. The incident was briefly discussed. In the IBC minutes, a new version of events appears, one that omits several critical details from the accident report. According to the IBC account, the postdoc's concern was said to have been that the tube (not cap) had cracked, but that thankfully, it hadn't. It was a mistaken impression by the young researcher. The tube was fine. And "the liquid on the tube"? It was "probably condensation". The broken cap isn't mentioned. Nor is the prematurely opened centrifuge. Nor is the decrease in the volume of the virus in the tube.
Condensation? According to the accident report, the "condensation" was observed not long after the tube was filled and almost immediately after it had been spinning at several hundred, perhaps several thousand, revolutions per minute. If it was condensation and not virus culture, then UT seems to have set a world laboratory record for the fastest-forming and most remarkably adhesive water condensation ever seen.
But as far as UT was concerned, the case was closed. No authorities were told. Officially, no accident took place, although despite the fact that nothing officially happened, UT curiously proceeded to decontaminate the entire lab "as if the contamination had occurred." The accident report remained labeled "draft" and was not finalized.
And there the story would have ended, before this Biosafety Bites.