study: Surgical masks don't protect against flu

[tropical]

On FluWiki,
from CTV.ca:
Surgical masks don't protect against flu: study
http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20071219/flu_masks_071219/20071219?hub=Health

Nurses want high-quality medical masks to protect themselves in the event of an avian flu outbreak.


Surgical masks don't protect against flu: study

Updated Wed. Dec. 19 2007 9:05 AM ET
The Canadian Press

A new report written for the Public Health Agency of Canada says there is no evidence surgical masks can protect against flu virus particles small enough to be inhaled into the lower respiratory tract or the lungs.

And the report says it's unclear how effective surgical masks are in blocking flu virus particles that are bigger and therefore likely to settle in the nose and throat of an exposed person.

The report is meant to serve as guidance to the public health agency on the question of how flu is transmitted and how best to protect against infection.

Federal, provincial and territorial health authorities need that kind of information to decide what kind of masks to stockpile to protect health-care workers during a flu pandemic -- cheap surgical masks or more expensive N95 respirators.

The panel says the scientific evidence remains unclear about how precisely flu is spread and what role exposure to bigger or smaller virus particles plays in transmission.

It concludes flu viruses are mainly transmitted over short distances and that more people become infected by inhaling viruses than by touching contaminated surfaces.

 

[gsgs]

Re: study: Surgical masks don't protect against flu

http://tinyurl.com/3ceylc

new study:

> Even cheap masks stop flu spreading

(it didn't work so well in 1918, though)



> Normal surgical masks help prevent people with the flu from
> spreading the virus just as well as more expensive face
> protection, a study shows for the first time.

very small study, only 28 people. And they just had to cough
on petri-dishes

 

[mixin]

Re: study: Surgical masks don't protect against flu

Tropical,
If you and others are interested, there is a 58 page Canadian study on influenza transmission and the role of ppe that I summarized here: http://www.setbb.com/fluwiki2/viewtopic.php?t=355&mforum=fluwiki2

 

[tropical]

Re: study: Surgical masks don't protect against flu

http://tinyurl.com/3ceylc

new study:

> Even cheap masks stop flu spreading

(it didn't work so well in 1918, though)

> Normal surgical masks help prevent people with the flu from
> spreading the virus just as well as more expensive face
> protection, a study shows for the first time.

very small study, only 28 people. And they just had to cough
on petri-dishes

That's 28 people experiment can't be statisticaly relevant. We can't name it as an study. After 100.000 people involved we can claim it's an statisticaly relevant study.

 

[gsgs]

Re: study: Surgical masks don't protect against flu

some more links, hattip to Dr.Dave :

Manikin-Based Performance Evaluation of N95 Filtering-Facepiece Respirators Challenged with Nanoparticles(Dec.05)


testing masks and restirators with NaCl-aerosols of size 40–1300nm(Mar.08)


Do N95 respirators provide 95% protection level against airborne viruses, and how adequate are surgical masks? (Mar.06)

 

[tropical]

Re: study: Surgical masks don't protect against flu

Tropical,
If you and others are interested, there is a 58 page Canadian study on influenza transmission and the role of ppe that I summarized here: http://www.setbb.com/fluwiki2/viewtopic.php?t=355&mforum=fluwiki2

Interesting summary, mixin.

An excerpt:
"Inhalable Particles:
Range in size from 0.1 to 100 um
Particles near 100 um deposit exclusively in the nasopharynx
Nasopharyngeal-sized particles, from 20 to 100 um, tend to travel no further than upper respiratory tract
Tracheobronchial-sized, from 10 to 20 um, may deposit as far down as the tracheobronchial region
Alveolar-sized, less than 10 um, may deposit anywhere, but are the only size capable of reaching the alveolar region
Depending on size, can stay in the air from seconds to days
Air currents may carry them considerable distances
Smaller particles evaporate faster."

Unfortunately, the item we are dealing on depends not only on if it is the best protection, but on money matters.

The best protection environment probably are:
- working rooms with negative air pressure, UV lights and decon. air filters
- autonomous air source inner the head mask, or rubber multiuse masks with changeable (one using) biological filters
- "use it one time" body clothes, or rubber multiuse, heavy gloves
- mandatory decontaminations of the body/head/rubber masks and clothes, before wearing off

How many will have the above? Only the pathologists, or the emergency teams, because of money costs. The other workers will must switch to cheaper forms of protections:
- instead of oxigen, or rubber masks, the Nxx ones, light gloves, ...

IMO for the "cheap" bioprotection:
- if the person is not an asthmatic one, N100 must be used (why insert the possibility of 5% contamination?)
- for heavy duty (sveating) working, an N100 with an exausted gas valve
- a person with an N mask must be aware of the many times cited input air entering holes created around the nose region when a person working heavy jobs, which would lead to contagion maybe
- considering to put an surgical mask above the N one, to collect the majority of big particles, in the intent to maybe reinforce the N100 filtering
- throwing the mask when the working using time is expired
- considering to put another pair of heavier gloves under the latex one, for escaping autoinfections when lift off the gloves (finger contacts with the outer latex surface), because there were no previous decontamination
- don't using the same (infected) gloves from an patient to another (this will be the dif. one in the entering tract).

Indeed, it must be a very much trained, and duty adicted personnel to cary out strictly this measures, but than, the hospital other infections will be cutted down also.