Why BSL-4 standards for researchers but not health care workers?

[Emily]

I still don't understand the reasoning. Does anyone else? Is it the cost of the equipment, or is it just too cumbersome in a hospital environment? I think the security workers had their own air supply and may have been at or close to BSL-4 protection in the video from the recent airliner scare.

http://www.usamriid.army.mil/biosafety/

— Biological Safety at USAMRIID —

Established in 1969, USAMRIID has decades of experience operating containment laboratories and has provided extensive training and consultation to other agencies setting up their own facilities. We consider safety—of our employees, our neighbors, and the surrounding community—our number one priority.

There are four levels of biological containment, ranging from Biosafety Level (BSL)-1, the lowest, to BSL-4, the highest. BSL-1 would be comparable to an open bench laboratory found in a school classroom—no special precautions would be needed. At BSL-2, USAMRIID employees wear laboratory coats and observe other basic precautions. For BSL-3 work, we require our personnel to change into scrub suits before entering the laboratory and take a complete shower before exiting. Other personal protective equipment may be required as well, depending on the tasks to be performed. BSL-4 is the highest level of containment, and employees wear positive-pressure suits commonly called "space suits" and breathe filtered air as they work.

Yet CDC's recommendations for HCW's are much less stringent.

http://www.cdc.gov/vhf/ebola/hcp/infection-prevention-and-control-recommendations.html

Why? Researchers warned in 1995 that modern hospital workers might have increased risk, rather than less risk than HCW's in more primitive facilities in ebola endemic areas.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1997182/pdf/ijexpath00004-0007.pdf

Int J Exp Pathol. Aug 1995; 76(4): 227–236.
PMCID: PMC1997182
Lethal experimental infections of rhesus monkeys by aerosolized Ebola virus.
E. Johnson, N. Jaax, J. White, and P. Jahrling

...

Our experiments were conducted at
240C and < 40% RH, conditions which are known to
favour the aerosol stability of at least two other African
haemorrhagic fever viruses, Rift Valley fever and Lassa
(Stephenson et a/. 1984; Anderson et a/. 1991). If the
same holds true for filoviruses, aerosol transmission is
a greater threat in modern hospital or laboratory
settings than it is in the natural climatic ranges of
viruses.

...

Regardless, we have shown that Ebola virus (Zaire
strain) can be transmitted by aerosol in an experimental
primate model. In light of the pathogenicity of human
filovirus infections, health care personnel at risk of
exposure should use precautions to minimize the risk
of aerosol exposure while managing acutely ill haemorrhagic
fever cases of unknown or filoviral aetiology.
The risk can be markedly reduced by adhering to sound
and practical infectious disease management procedures.
This requires curtailing aerosol generating procedures;
using protective clothing, including gloves and
masks; adequately decontaminating potentially infectious
material; and conducting virus diagnostic procedures
in regional containment facilities capable of safely
handling highly hazardous infectious agents (Comperts
et a/. 1978; CDC 1988).

And even in that warning, I still don't see why BSL-4 standards were not recommended. Also, I'm not sure why they ruled out simultaneous ocular infection in the monkeys since I don't see that their eyes were protected in the head exposure chambers.

It would be comforting to know that this experiment that involved considerable animal suffering had resulted in protection of modern hospital workers, but I don't see that result so far.

 

[AlaskaDenise]

Re: Why BSL-4 standards for researchers but not health care workers?

Perhaps the media can pose this question to the CDC.

,

 

[AnnaLisa]

Re: Why BSL-4 standards for researchers but not health care workers?

Good question.

 

[Graupel]

Re: Why BSL-4 standards for researchers but not health care workers?

The simple reality that there are only handful of BSL4 beds in the entire country- it is just a total and complete impossibility.

I think the MSF systems in W Africa would be something like BSL3+.

 

[Vibrant62]

Re: Why BSL-4 standards for researchers but not health care workers?

I dont personally think its a question of 'beds', its a question of the protection afforded to health workers whilst giving care. Negative pressure rooms are not needed - just spaces where good isolation and good healthcare can be provided.

We could have patients treated in nursing homes or isolation centers, but the HCWs would still need level 3+ or 4 PPE, complete with assistants. That means that they all need training in its appropriate use, and if that is too difficult, perhaps we need designated teams within the general hospital staff who are willing to provide care and are subject to additional training, who can provide care if and when an ebola patient is confirmed.

 

[Emily]

Re: Why BSL-4 standards for researchers but not health care workers?

I was thinking of the suits, too, Vibrant. Someone who used to work at Harborview in Seattle some time ago thought they had moon suits available, but they certainly do not now, if they ever did.

http://www.kirotv.com/news/news/ebola-outbreak-changes-hospital-protocol/ngwWF/

Updated: 11:48 a.m. Wednesday, Aug. 6, 2014 | Posted: 7:05 p.m. Tuesday, Aug. 5, 2014
By Graham Johnson
Ebola outbreak changes hospital protocol

...

"Over a month ago we would have been laughing (at the idea of) Ebola coming in with patients at Harborview, but now we take it very seriously," said Dr. John Lynch, Harborview's Medical Director of Infection Control.
...
More relevant is a separated waste stream from the room, and protocols for medical personnel to wear and dispose of protective clothing.

Those coverings are not as dramatic as 'moon-suits' that have been used in Africa or during the transportation of two American patients to Atlanta for treatment.

Lynch says those suits have been worn in non-controlled areas and are not needed in American hospitals.

"These are basic blood and body fluid precautions that we can easily take in any hospital in the country," Lynch said....

Bet he's not saying that anymore.

 

[Graupel]

Re: Why BSL-4 standards for researchers but not health care workers?

And seriously, if Harborview has limited capacity and is scrambling to address these issues?

 

[Vibrant62]

Re: Why BSL-4 standards for researchers but not health care workers?

On the bright side, its good that these issues are coming to light NOW so that there is time for them to be addressed and for hospitals (not just in the US) to prepare properly.

A tradgedy for the nurses who have been infected though...

 

[Emily]

Re: Why BSL-4 standards for researchers but not health care workers?

It was shocking to read that about Harborview. I've been thinking it won't happen here because we have Harborview. They have time to prepare, yet is it possible to care safely for a dying Ebola patient? The success stories in terms of no HCW infections in the US all involved caring for patients who did not get sick enough to die.

I just don't think standard hospitals have the philosophical bent to deal with this. Their lifesaving mission will not allow them to stand back when they should.

 

[Dani]

Re: Why BSL-4 standards for researchers but not health care workers?

It was shocking to read that about Harborview. I've been thinking it won't happen here because we have Harborview. They have time to prepare, yet is it possible to care safely for a dying Ebola patient? The success stories in terms of no HCW infections in the US all involved caring for patients who did not get sick enough to die.

I just don't think standard hospitals have the philosophical bent to deal with this. Their lifesaving mission will not allow them to stand back when they should.

I think you nailed it. In Texas, they did everything possible, and now it may be that doing everything that's possible is exactly the wrong thing to do. It may be that standard protocol for Ebola in 2015 is no intubation, no ventilation. But it isn't in 2014. Choosing between the staff and the patient is not something we have had to do in this country, not in my lifetime. This is for academicians and ethicists.

 

[Emily]

Re: Why BSL-4 standards for researchers but not health care workers?

http://www.foxnews.com/politics/2014/10/19/fauci-tries-to-calm-us-after-missteps-on-ebola-amid-concerns-americans-have/

Fauci tries to calm US after missteps on Ebola, amid concerns Americans have lost faith
Published October 19, 2014
FoxNews.com
...
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told ?Fox News Sunday? that the adopted World Health Organization protocol for handling an Ebola patient was better suited for field work than confined hospital care....

 

[Vibrant62]

Re: Why BSL-4 standards for researchers but not health care workers?

Accepted that some aspects may need adaptation to a hospital space, but I fail to understand why MSF protocols cannot be applied in a hospital setting.

It may require some reconfiguration of space. The critical part of PPE seems to be PPE that covers all parts of the body and a buddy system and disinfection at each stage of doffing.

Whilst case numbers are low, having regional centers for transfer once patients are identified would seem sensible, where staff can have had additional training, along the same lines as MSF teams.

Can someone please explain to me why this is not possible?

 

[Nox]

Re: Why BSL-4 standards for researchers but not health care workers?

In Quebec we have each a pediatric and adult hospital designated to treat eventual Ebola cases. These designated hospitals were announced early September- before the Texas case. By having designated centres, only the ER staff needed extra training and designated negative pressure isolation room off the ER before a transfer could take place. This allows for resources to be allocated in an efficient manner to those on the front line and care education to happen at the targeted hospitals.

 

[AlaskaDenise]

Re: Why BSL-4 standards for researchers but not health care workers?

Accepted that some aspects may need adaptation to a hospital space, but I fail to understand why MSF protocols cannot be applied in a hospital setting.....

I agree about the differences in protocol application - in fact I would expect the opposite.

.

 

[sharon sanders]

Re: Why BSL-4 standards for researchers but not health care workers?

Please see:

CDC - Guidance on Personal Protective Equipment To Be Used by Healthcare Workers During Management of Patients with Ebola Virus Disease in U.S. Hospitals, Including Procedures for Putting On (Donning) and Removing (Doffing) - October 20, 2014

 

[Emily]

Re: Why BSL-4 standards for researchers but not health care workers?

I'm not sure what to make of this - is ebola no longer a BSL-4 pathogen?

http://annals.org/article.aspx?articleid=1918777

Kortepeter MG, Smith PW, Hewlett A, Cieslak TJ. Caring for Patients With Ebola: A Challenge in Any Care Facility. Ann Intern Med. [Epub ahead of print 16 October 2014] doi:10.7326/M14-2289

Since the first reported outbreaks of Marburg (1967) and Ebola (1976), there has been an evolution in our thinking about the optimal personal protective measures for medical staff caring for patients infected with these viruses. From 1972 to 2010, a high-level containment care (HLCC) unit at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), often called ?the slammer,? was considered the gold standard for such care. The unit's engineering controls were modeled after a biosafety level?4 (BSL-4) laboratory, with positive-pressure ?space? suits, compressed in-line air, HEPA filtration, a decontamination shower, ultraviolet light pass boxes, an airlock, and antiseptic dunk tanks for movement of items in and out of the containment area. Toilet waste was discharged into the laboratory sewer system, and the facility possessed its own autoclave, operating room, and bedside laboratory. These built-in capabilities significantly reduced logistics challenges and provided reassurance that nosocomial spread could be reduced to near zero. Given the relatively high percentage of caregivers who have died of filoviral and other BSL-4 virus infections in the field, and the prior uncertainty in whether such high infection rates might be caused by droplet or airborne spread, utilization of such a containment facility seemed reasonable. Although used on occasion to quarantine field workers potentially exposed to highly hazardous viruses, the unit was used primarily for isolating individuals exposed to a BSL-4 virus in the laboratory. During the unit's 38 years of operation, 21 patients were quarantined after potential exposures?and none became ill (3).

Over time, we learned that the spread of filoviruses occurs primarily by direct contact with blood and body fluids (1). Thus, it was determined that a patient care facility with the full panoply of BSL-4 laboratory?like features was no longer needed. The facility was decommissioned and refurbished as a training facility for scientists working in the institute's containment laboratories...

Did they decide that no BSL-4 pathogen could ever evolve?

 

[zincfinger]

Re: Why BSL-4 standards for researchers but not health care workers?

The difference in requirement for research facilities and hospitals is that research labs are often working with pathogens that are not already present in the community. In that case, accidental release into the community could be the start of an entirely new outbreak.

In contrast, infection of an HCW from a patient is another new case for a disease already present in the community. In such a case the community will already be prepared, or in the process of preparing to deal with the disease and already aware of the danger.

It's the same contrast of the seriousness of igniting a fire in a fire hazard area in which there is currently no fire with igniting a fire in an area in which there is already a wildfire burning. In the former situation you have created a very serious problem that was not previously present at all. In the latter case you've exacerbate (probably only very slightly) a situation already present.

The difference is of little consequence to patients, of course, but to the community it is huge.

the cost of preventing an event must be related both to the probability of it and the consequences should it occur.