With the H5 controversy of the last few months, there has
been some talk about moving the mammalian transmissible or even all highly pathogenic flu viruses into BSL4 laboratories. Here is why it’s a terrible idea.
BSL3, BSL3+, BSL4: What’s the difference?
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BL3 personal protection |
BSL3 is a lab that has certain safety and containment
features that go above and beyond a typical molecular biology or chemistry lab
(typically BSL2). BSL3 labs are
required to be behind double locked doors. The lab space is required to be
maintained under a negative air pressure so that opening doors or unintentional
breach of containment causes air to be pulled into the lab as opposed to
it (and what ever is in it) being
blown out of the lab. Additionally, all waste generated is required to be recovered
and decontaminated prior to disposal.
Finally, all personnel working in a BSL3 lab are required to wear
additional personal protective equipment (PPE). This includes disposable lab
coats, multiple disposable shoe covers and multiple gloves, as well as surgical
style facemask.
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Bl3+ personal protection |
BSL3+, other wise known as BSL3 agriculture or BSL3
enhanced, has significant upgrades to the security and safety measures of
BSL3. A BSL3+ is required to have
a pass through autoclave so that all solid waste is decontaminated prior to
leaving the facility. The researchers body is the only thing that leaves BSL3+
without going through the autoclave (with very few exceptions and only with
proper permission and safety protocols).
The scrubs they wear under their PPE are removed in the facility and the
researchers are required to shower out in order to leave. PPE is similar to
BSL3 but also include a Tyvek coverall and a loose fitting overhead PAPR
(powered air purifying respirator) that is equipped with a HEPA filter to scrub
the air they breathe. The facility is sealed airtight and all rooms are
monitored for pressure changes multiple times a day and the air itself is
double HEPA filtered. The entire facility can be decontaminated via gas decon
ports from the outside. All security features have built in redundancies and
back ups. Prior to gaining access
to a BSL3+ lab, a worker must undergo extensive training and testing and must
pass an FBI background check.
A BSL4 lab is the highest level of biosafety and containment
possible. It includes all the
elements of a BSL3+ lab with two main differences. Researchers are required to
wear a fully sealed suit that air is pumped into from either the outside or a
sealed air tank. These are the
moon suits you see in movies like ‘Contagion’ or ‘Outbreak’. Additionally, the researchers take a
chemical decontamination shower to exit the lab.
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BL4 personal protection |
Where should it be?
Currently all work done in the US or with US grant money
utilizing highly pathogenic influenza is performed under BSL3+ conditions. All facilities are inspected annually
by relevant agencies depending on the pathogens in use. This can include the
CDC, NIH, USDA and others. Are these safety features enough for these viruses? BSL3
and BSL4 are reserved for work with pathogens that can cause severe to fatal infections
in humans. The difference between
BSL3 and BSL4 is that BSL3 agents have known and effective treatment strategies
and BSL4 agents do not. The only
exception being smallpox in BSL4 due to the fact that it has been eliminated
from nature. With this in mind, where
should mammalian transmissible H5N1 or all highly pathogenic influenza strains be? There is no doubt that highly
pathogenic influenza is a very deadly pathogen. The ability to become airborne
means standard BSL3 conditions are probably not adequate protection. However the use of PAPRs in BSL3+ are
capable of filtering virus out of the air. The research done with these viruses is very clear. The drugs and vaccines we currently
have are still very effective against these strains making BSL4
inappropriate. Finally, highly
pathogenic influenza is found readily in nature. Humans are exposed to it
daily. All of this leads to one
very clear conclusion: Highly
pathogenic avian influenza, mammalian transmissible or not, does not belong in
BSL4. BSL3+ is sufficient protection. A move to BSL4 would be unnecessarily
disastrous, not only to influenza research, but also all current BSL4
pathogens. A move to BSL4 would
kill many flu labs do to a lack of appropriate facilities. Those flu researchers
who would still have access to BSL4 facilities would then be jockeying for time
and space inside the facilities that already house other research groups. Retarding research on understanding
the most dangerous pathogens is an indescribably terrible idea.
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Even Charles Barkley knows the move is a bad idea. |
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