no evidence surgical masks protect against flu

[Guest guest]

Expert panel concludes there is no evidence surgical masks protect

against flu Dec 19, 2007

TORONTO - Surgical masks aren't adequate to protect people from

becoming infected during an influenza pandemic, a panel of experts

said in a report released Wednesday.

The report, written for the Public Health Agency of Canada, suggested

industrial respirators known as N95s would be needed to minimize the

risk of transmission of flu.

" Surgical masks don't really fit the bill, " said Dr. Low, chair

of the panel which brought together infection control specialists,

nurses and occupational health and safety experts.

" Even if they have a good filtering capacity, inhalable (virus)

particles - because they're not affected by gravity - will take the

route of least resistance, which will be around the mask and through

the gap that exists between the surgical mask and the face. "

The panel was asked to advise the public health agency on one of the

most contentious issues in influenza science - how flu spreads.

The answer will be used to craft guidance for provinces and

territories on what protective equipment they should consider

stockpiling for health-care workers in a pandemic as well as advice

for the public on how to reduce the risk of getting sick in such an event.

A senior official with the public health agency said the report is one

piece of information the organization will use to update the

recommendations on infection control in health-care delivery contained

in one of the annexes of the Canadian pandemic influenza plan.

Other items that will factor into the mix when that advice is being

updated include the cost and availability of N95 respirators, how

money spent on more expensive respirators might otherwise be spent as

well as whether there are any unintended negative consequences of

their use, said Dr. Arlene King, the director general of pandemic

preparedness.

" There is a ream of other issues that need to be considered as we move

forward with developing and finalizing and revising the guidelines, "

said King, who noted the current intention is to publish the updated

guidelines in the spring.

An N95 respirator is roughly 10 times as expensive as a surgical mask.

The panel was asked to answer two questions: how and where seasonal

and pandemic influenza are transmitted and what role N95 respirators

and surgical masks could play in blocking transmission. It did not

conduct or commission new research, but rather analyzed the available

scientific literature.

That evidence is sparse, inconclusive and hotly debated, used by both

sides in a polarized debate about whether flu viruses waft through the

air over distances or are mostly spread in heavy droplets sneezed or

coughed at closer range into the mucus membranes of uninfected people.

The debate has been reignited in the pages of major international

medical journals over the past couple of years, with Toronto-based

scientists Dr. Tellier of the Hospital for Sick Children and

Dr. Gardam of University Health Network expressing opposing views.

Both were on the expert panel. Still, the group managed to come to a

consensus opinion.

Low suggested the compromise involved reframing the issue to look at

whether viruses small enough to be inhaled deep into the respiratory

tract can be generated by a person sick with flu.

The panel concluded that was possible, though likely those viruses

would travel through the air only a short distance - within an

estimated two metres.

" But it doesn't rule out the possibility that at short ranges, that

these viruses can still cause disease, " said Low, chief microbiologist

at Toronto's Mount Sinai Hospital.

" They can still get into the respiratory tract. "

If inhalation has to be considered as one of the routes of

transmission of influenza, then properly fitted N95 respirators are

the appropriate form of protection, the panel concluded. That's

because properly fitted respirators create a seal between the face and

the device.

In August the Ontario government announced it was buying 55 million

N95 respirators for its emergency stockpile to protect front line

health-care workers in a medical emergency such as a flu pandemic or

another SARS-like outbreak.

The expert panel's guidance doesn't pertain strictly to health-care

settings, though the Canadian pandemic plan does not currently take a

stance on whether the public ought to stock up on masks or respirators

for use in a pandemic.

" We don't come out one way or the other with respect to the use of

masks by the public, " said King. " But we understand that people may

choose to wear masks during a pandemic. "

Low said if he were asked to translate the expert panel's conclusions

for the general public, he'd suggest people caring for infected

persons at home during a pandemic wear an N95 respirator.

" If you're on the streets, on a bus, going to work - that's a

different scenario. The type of contact is different, the risk is

different, " he said, noting the guidance is similar to the advice the

Centers for Disease Control have issued in the United States.

" For where we are today in understanding this, I think that's a pretty

good stance. "

http://canadianpress.google.com/article/ALeqM5hiGd5y10q2koRd1ebSBjZI2UFZAg

[Guest guest]

When I was studying infection control I learned that the mask definitely will not block stuff from passing through it fibers. The mask's main purpose, so the instructor told the class, is to remind people to keep their hands away from their faces. The super-duper respirators are indeed the best "masks" to block germs.Lee <jackalope_lepus@...> wrote: Expert panel concludes there is no evidence surgical masks protectagainst flu Dec 19, 2007TORONTO - Surgical masks aren't adequate to protect people frombecoming infected

during an influenza pandemic, a panel of expertssaid in a report released Wednesday.The report, written for the Public Health Agency of Canada, suggestedindustrial respirators known as N95s would be needed to minimize therisk of transmission of flu."Surgical masks don't really fit the bill," said Dr. Low, chairof the panel which brought together infection control specialists,nurses and occupational health and safety experts."Even if they have a good filtering capacity, inhalable (virus)particles - because they're not affected by gravity - will take theroute of least resistance, which will be around the mask and throughthe gap that exists between the surgical mask and the face."The panel was asked to advise the public health agency on one of themost contentious issues in influenza science - how flu spreads.The answer will be used to craft guidance for provinces andterritories on what

protective equipment they should considerstockpiling for health-care workers in a pandemic as well as advicefor the public on how to reduce the risk of getting sick in such an event.A senior official with the public health agency said the report is onepiece of information the organization will use to update therecommendations on infection control in health-care delivery containedin one of the annexes of the Canadian pandemic influenza plan.Other items that will factor into the mix when that advice is beingupdated include the cost and availability of N95 respirators, howmoney spent on more expensive respirators might otherwise be spent aswell as whether there are any unintended negative consequences oftheir use, said Dr. Arlene King, the director general of pandemicpreparedness."There is a ream of other issues that need to be considered as we moveforward with developing and finalizing and revising the

guidelines,"said King, who noted the current intention is to publish the updatedguidelines in the spring.An N95 respirator is roughly 10 times as expensive as a surgical mask.The panel was asked to answer two questions: how and where seasonaland pandemic influenza are transmitted and what role N95 respiratorsand surgical masks could play in blocking transmission. It did notconduct or commission new research, but rather analyzed the availablescientific literature.That evidence is sparse, inconclusive and hotly debated, used by bothsides in a polarized debate about whether flu viruses waft through theair over distances or are mostly spread in heavy droplets sneezed orcoughed at closer range into the mucus membranes of uninfected people.The debate has been reignited in the pages of major internationalmedical journals over the past couple of years, with Toronto-basedscientists Dr. Tellier of

the Hospital for Sick Children andDr. Gardam of University Health Network expressing opposing views.Both were on the expert panel. Still, the group managed to come to aconsensus opinion.Low suggested the compromise involved reframing the issue to look atwhether viruses small enough to be inhaled deep into the respiratorytract can be generated by a person sick with flu.The panel concluded that was possible, though likely those viruseswould travel through the air only a short distance - within anestimated two metres."But it doesn't rule out the possibility that at short ranges, thatthese viruses can still cause disease," said Low, chief microbiologistat Toronto's Mount Sinai Hospital."They can still get into the respiratory tract."If inhalation has to be considered as one of the routes oftransmission of influenza, then properly fitted N95 respirators arethe appropriate form of

protection, the panel concluded. That'sbecause properly fitted respirators create a seal between the face andthe device.In August the Ontario government announced it was buying 55 millionN95 respirators for its emergency stockpile to protect front linehealth-care workers in a medical emergency such as a flu pandemic oranother SARS-like outbreak.The expert panel's guidance doesn't pertain strictly to health-caresettings, though the Canadian pandemic plan does not currently take astance on whether the public ought to stock up on masks or respiratorsfor use in a pandemic."We don't come out one way or the other with respect to the use ofmasks by the public," said King. "But we understand that people maychoose to wear masks during a pandemic."Low said if he were asked to translate the expert panel's conclusionsfor the general public, he'd suggest people caring for infectedpersons at home during a

pandemic wear an N95 respirator."If you're on the streets, on a bus, going to work - that's adifferent scenario. The type of contact is different, the risk isdifferent," he said, noting the guidance is similar to the advice theCenters for Disease Control have issued in the United States."For where we are today in understanding this, I think that's a prettygood stance."http://canadianpress.google.com/article/ALeqM5hiGd5y10q2koRd1ebSBjZI2UFZAg . Do one thing every day that scares you. Eleanor Roosevelt