Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

[Giuseppe]

Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers. (Ann Intern Med., edited)

[Source: US National Library of Medicine, (LINK). Edited.]

Ann Intern Med. 2010 Mar 16;152(6):JC32.

Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

[No authors listed]

PMID: 20231556 [PubMed - in process]
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[Laidback Al]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

The text is not available but the title of the article indicates that surgical masks performed as well as N95 masks for protection from influenza (presumably H1N1). In lay person's terms, noninferior roughly translates to "at least, or almost equal to".

Definition of non-inferiority clinical trial

Non-inferiority clinical trial: A clinical trial that shows that a new treatment is equivalent to standard treatment. Also called a non-inferior trial. See: Clinical trials. See also: Inconclusive clinical trial; Negative clinical trial; Positive clinical trial.

http://www.medterms.com/script/main/...ticlekey=39072

and see this discussion regarding noninferiority for randomized trials from JAMA - Reporting of Noninferiority and Equivalence Randomized Trials (2006) (bolding added)

. . . Most RCTs aim to determine whether one intervention is superiorto another. By contrast, equivalence trials⁸ aim to determinewhether one (typically new) intervention is therapeuticallysimilar to another, usually an existing treatment. We use newto refer to the treatment under test, and the comparison orreference treatment is often called an active control. A noninferiority trial seeks to determine whether a new treatmentis no worse than a reference treatment. Because proof of exactequality is impossible, a prestated margin of noninferiority() for the treatment effect in a primary patient outcome isdefined. Equivalence trials are very similar, except that equivalenceis defined as the treatment effect being between ? and. True (2-sided) equivalence therapeutic or prophylactic trialsare rare because most such trials address the question of noninferiority.
In trials that investigate noninferiority, the question of interestis not symmetric.⁹ The new treatment will be recommended ifit is similar to or better than an existing one, but not ifit is worse (by more than ). Superiority of the new treatmentwould be a bonus. This article focuses mainly on noninferioritytrials but applies also to 2-sided equivalence trials.
Noninferiority trials are intended to show whether a new treatmenthas at least as much efficacy as the standard or is worse byan amount less than , often on the premise that it has someother advantage, eg, greater availability, reduced cost, lessinvasiveness,^10-11 fewer side effects (harms),¹² or greaterease of administration,¹³ for instance, one daily dose ratherthan 2 doses¹⁴ or more than 2 doses.¹⁵ Some noninferiority trialshave been criticized for merely studying a new marketable product("me-too" drugs).¹⁶
Noninferiority and equivalence trials are not limited to drugs.For example, a new antenatal care model with fewer clinic visitsand reduced cost was investigated for its equivalence to thestandard model as regards maternal and neonatal outcomes.¹⁷A noninferiority trial compared 2 interventional strategiesfor coronary revascularization in diabetic patients. . .

http://jama.ama-assn.org/cgi/content/full/295/10/1152

[gsgs]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

no authors listed, no abstract - a new advanced dimension of secrecy


isn't that the same study, which we discussed earlier ?

searching the link ...


well, I think I meant this: http://www.ncbi.nlm.nih.gov/pubmed/19797474
full text here: http://jama.ama-assn.org/cgi/content/full/302/17/1865

Among 478 nurses, surgical masks were noninferior to N95 respirators for protection against laboratory-
confirmed cases of influenza (pp. 1865-71).

[gsgs]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

Related articles:
-----------------------
Surgical mask vs N95 respirator for preventing influenza among health care workers:
a randomized trial. JAMA. 2009 Nov 4; 302(17):1865-71. Epub 2009 Oct 1.

http://www.ncbi.nlm.nih.gov/pubmed/19797474

http://jama.ama-assn.org/cgi/content/full/302/17/1865

In vivo protective performance of N95 respirator and surgical facemask.
Am J Ind Med. 2006 Dec; 49(12):1056-65.

http://www.ncbi.nlm.nih.gov/pubmed/17096360

Respiratory performance offered by N95 respirators and surgical masks: human subject evaluation with NaCl aerosol representing bacterial and viral particle size range.
Ann Occup Hyg. 2008 Apr; 52(3):177-85. Epub 2008 Mar 7.

http://www.ncbi.nlm.nih.gov/pubmed/18326870

http://annhyg.oxfordjournals.org/cgi/content/full/52/3/177

ReviewProtecting healthcare workers from pandemic influenza: N95 or surgical masks?
Crit Care Med. 2010 Feb; 38(2):657-67.

http://www.ncbi.nlm.nih.gov/pubmed/20095070

ReviewFace masks to prevent transmission of influenza virus: a systematic review.
Epidemiol Infect. 2010 Apr; 138(4):449-56. Epub 2010 Jan 22.

http://www.ncbi.nlm.nih.gov/pubmed/17697389

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2040158/?tool=pubmed

(pubmed gives silly long links, but you can cut them after the first "?")

[mixin]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

No screcy involved.. just money
or wait 6 months to see if it's free.

Buy the article here:

http://www.annals.org/content/152/6/JC3-2.citation

[gsgs]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

you would buy a pig in a poke.
No authors, no abstract.

Purchase Short-Term Access
Pay per Article - You may access this article (from the computer you
are currently using) for 1 day for US$15.00.

and you won't be able to quote and discuss here

[Laidback Al]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

you would buy a pig in a poke.
No authors, no abstract.

Purchase Short-Term Access
Pay per Article - You may access this article (from the computer you
are currently using) for 1 day for US$15.00.

and you won't be able to quote and discuss here

I agree with gsgs. How can one make an informed decision about whether a journal article is worth the price of a single-use download without an abstract or at least knowing who are the authors of the report.

[tropical]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

there were already a ft thread about such assertions (stated by US Inf. ...),
also unbelievable, and with a study possible bias methodology of inputs factors inclusion possibility

IMO, personaly,
I shall never swallow,
that an ordinary surgical mask
with plain opticaly obvious air holes from nose/ears head positions,
additionaly handled as an lift up/down during work object,
could be equal as an N95 (better filtering material, or added filter) good circumvently sealed and handled mask.

[gsgs]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

the seal is just a matter of handling, I assume this study is only about the
filtering material.
You can always close the lecks, I assume the best way would be to use
another mask into which the surgical mask (or N95?)is just inserted
as a filter.

Easierst would be to just use adhesive tape and fix it to the skin but maybe
uncomfortable. Another suggestion was nylon-stockings over the mask,
but maybe also uncomfortable and socially not yet accepted

[tropical]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

the seal is just a matter of handling, I assume this study is only about the
filtering material.
You can always close the lecks, I assume the best way would be to use
another mask into which the surgical mask (or N95?)is just inserted
as a filter.

Easierst would be to just use adhesive tape and fix it to the skin but maybe
uncomfortable. Another suggestion was nylon-stockings over the mask,
but maybe also uncomfortable and socially not yet accepted

as you said about the additional "patches":
uncomfortable/not accepted
and
not allowed if we must compare the exact appearance and usage of:
surgical versus N95 resp.m.

about the filtering material,
what is the point even of having the same filtering material, if you than sabotate it by an "open windows" mask construction?

additionaly, when you saw an P2/3 mask thickness, or the compactness of the one with the applyed filter,
versus the ordinary surgical mask (even more quality one),
the doubts easily vanish ...
(production leaflets included)

about the "You can always close the lecks"
I have big doubts that after adesive applyings you can than lift it off ...

and about the 2 masks seting,
than it is not an surgical versus N95 evaluation story.

P.S.
I wroted few times the previous years, of an possible additional applying of a surgical mask over an N95 (thing usualy not performed),
only because of preserving for a little time more the N one,
by the surgical one taking the first impact of the coughed incoming splashing droplets, in case of need only (N masks shortage).

[german-docter]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

I'd really like to agree with Laidback Al (posts #2 and 7) gsgs (post #6) and tropical (post#8)...

...and personally, I would always prefer a well-fitting N95 respirator as personal protective equipment (PPE) instead of a surgical mask, and I reiterate what I wrote about non-inferiority studies:

Quote (post # 3) thread :
Surgical masks versus N95 respirators, and the problem of non-inferiority studies

http://www.flutrackers.com/forum/showthread.php?t=127810&highlight=Surgical+masks+versus+N95+respirators+problem+non-inferiority+studies

The intention of a "non-inferiority study design" is NOT to investigate what would really be the best protection device (head to head) but only to argue that device A (ordinary surgical masks) probably is not inferior to device B (N95 respirators).

If the difference in the devices' power to prevent influenza transmission would be low you would need much more cases to come to a clear result in favour of one of the two devices.

So, surgical masks seem to be "not inferior" or "not as much inferior" to N95 respirators.
But N95 respirators really still might be superior to ordinary surgical masks (and IMO probably will be).

------------------------------------------

If you were a manufacturer of surgical masks you certainly would like to fund a "non-inferiority study".
If you were a health care worker you probably would like to know what would be the real "best protection device".
And if you were a health care institution (e.g. hospital) with a low budget ?

related link: CDC update March 10, 2010:

http://www.cdc.gov/h1n1flu/guidelines_infection_control.htm

CDC: Interim Guidance on Infection Control Measures for 2009 H1N1 Influenza in Healthcare Settings, Including Protection of Healthcare Personnel
March 10, 2010, 4:00 PM ET

[mixin]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

Another suggestion was nylon-stockings over the mask,

I tested the nylon stocking over an N95 to see if it made a better seal, which I thought it did. It wasn't anymore uncomfortable than just an N95 alone. This would be good in case one of the elastic bands broke.

I'm not sure how well a nylon would work with a surgical mask, though. It might fit too tight to the nose and mouth, making it difficult to breathe.

[tropical]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

I tested the nylon stocking over an N95 to see if it made a better seal, which I thought it did. It wasn't anymore uncomfortable than just an N95 alone. This would be good in case one of the elastic bands broke.

I'm not sure how well a nylon would work with a surgical mask, though. It might fit too tight to the nose and mouth, making it difficult to breathe.

ehm, that's precisely the main problem:
if too tight, it is hard breathing,
but if it is not 100% tight, than you breath directly infected air without any filtering,
nor from the mask tissue, nor from the resp. mask filter,
so if there are contaminated dust particles, you will inhale them,
the remaining mask tissue would absorb only a splashed part of greather particles (after further infecting the deeper/bottom mask layers to skin).

if talking of sealed face masks, anything but rubber/.../ material, would not stick the skin sealed any mask enaugh good, if at hard work ...

___

Comparison of powered and conventional air-purifying respirators during simulated ...

http://emj.bmj.com/content/26/7/501.abstract

[gsgs]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

you would inhale _some_ unfiltered air/dust, but fewer.
Even if filtered, it's only 95%.
Also just the decision when and how long to put the mask on
includes "leakage".
So 5% leakage is tolerable

[tropical]

Re: Ann Intern Med. Surgical masks were noninferior to N95 respirators for preventing influenza in health care providers.

personaly, 5% of inhaled contaminated air,
could be a reasonable risk only to persons which resp. tract are compromised in a way that they can't breath with an N100% filter or layer

how long to tolerate the mask on,
is an period stated by the producer,
or it vary if prematurely saturated by the contaminants (~ became harder for breathing during usage)

it is good policy have masks with an exhaust ventil,
because of heavy sweating during any work but typing the pc
(additional problem if glasses are on, and not tight the mask)

the inhalation of unfiltered contaminated air dusted particles because of an wrong or unsealed mask, or the voluntary "take a breath" biosec. breaches leakeages,
is a nobrain dangerous usage of a respiratory tract shielding mask (where surgical only are dangerous) - if in a heavy contaminated closed environment,
but I agree that it is dificult to achieve/constrict the workforce to be perfect in its usage, and the systems their purchasing in mass quantities

that's why the masks alone can't solve the problem (if not air streamed, or whole face glass/filter masks)