Mutant H5N1 Virus Stirs Biosafety Debate
While research on the lab-altered H5N1 virus that can be transmitted between mammals in laboratories is put on hold, scientists are debating how to balance biosecurity with the need for research that could help thwart a pandemic.
The issue: What biosafety containment level (BSL) should be used for the viruses?
The levels range from BSL-1 to BSL-4, which are designated in ascending order by degree of protection provided to lab personnel, the environment and the community. Biosafety levels apply to labs dealing with infectious microbes.
Currently, studies with these viruses, which were engineered to spread via respiratory droplets between ferrets, are being done at BSL-3 or higher facilities. However, Canada has already moved to institute the highest level of biosafety containment research for these viruses, writes Arturo Casadevall, editor in chief of the journal mBio, the journal in which commentaries on the subject appear on Tuesday (March 6).
Casadevall lays out the dilemma: "BSL-4 containment would theoretically protect society by increasing both biosafety and biosecurity. However, at the same time, this very high level of containment would make society potentially more vulnerable, since critical experimental work will not get done simply because BSL-4 facilities are few in number and already engaged in research with numerous other pathogens."
In the hopes of understanding how H5N1, which primarily infects birds, could mutate into a disease that passes easily among humans, and so could cause a flu pandemic, scientists in two separate labs modified the virus so it could spread airborne between ferrets. In one case, the infection killed the ferrets, in the other it did not. It's not known if these viruses could infect humans. [Predicting the Next Major Virus]
While some maintain this research is crucial to preventing or mitigating an H5N1 pandemic, others fear this work could lead to an accidental release of the mutant virus or fall into the wrong hands.
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In December, the U.S. National Science Advisory Board for Biosecurity (NSABB) requested that details of the studies be withheld from publication in the journals scheduled to publish them. Casadevall is a member of NSABB.
Flu scientist Adolfo García-Sastre of the Mount Sinai School of Medicine, argues BSL-4 is excessive and would stifle important research. He points out both vaccines and anti-virals are available to prevent or treat human H5N1 infections.
Enhanced BSL-3 facilities offer the necessary security measures, including interlocked rooms with negative pressure, air circulation systems filtered for tiny particles, and appropriate decontamination and/or sterilization practices for material leaving the facility, García-Sastre argues.
However, since these viruses can transmit easily between mammals, Michael Imperiale and Michael Hanna of the University of Michigan argue for BSL-4 containment, the highest level available.
The vaccine for H5N1 is not widely available, and drug resistance and a slow distribution system for antiviral drugs mean a small outbreak could not be contained, they contend.
Although, World Health Organization statistics say nearly 60 percent of human cases of H5N1 resulted in death, virologists say it is most likely much less deadly.
At a meeting in February, flu scientists and health officials decided the research should be published in full, and research resumed, after a delay intended to address anxieties raised by the research and re-assess the biosafety and biosecurity conditions necessary for this kind of work.
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