Birdflu Mailing List: N95 Masks and other Interventions Reduce Flu Transmission

[William Weir (wweir1]

Important:  The British Medical Journal (*BMJ*. 2009;339:b3675) reported
this month on the effectiveness of several interventions to reduce
transmission of epidemic respiratory infection, such as H1N1 flu.

The Medscape Medical News report today may be found at
http://www.medscape.com/viewarticle/709386?sssdmh=dm1.533222&src=nldne&uac=138864FX&uac=138864FX

Below is my reformatting of MMN's with my comments on the N95 respirator
mask and some phrases embolded.
Also, below is the one-page sign to be placed with a few N95 masks at the
entrances to our meeting rooms "Do you have any flu-like symptoms?" It has
been reviewed for accuracy and improvements by several experts, but if you
find a way to improve it, please send it to me.  If you want a copy of
either of these in print-ready MS Word format, please let me know at
wweir1 [at] gmail.com  (This discussion list does not allow for attachments.)

If you receive this without having subscribed to this MN UU Social Justice
Alliance discussion group, I have listed you in Bcc: and invite you to let
me know if you care to be in this discussion group.  If so, you will receive
occasional emails from me or another subscriber referencing what may be
valuable in our effort to reduce the toll of pandemic flu, now the novel
strain nH1N1 and possibly later the more virulent "bird flu" strain H5N1.

My previous email contained the one-page sign to be placed with a few N95
masks at the entrances to our meeting rooms "Do you have any flu-like
symptoms?" I have added its update below.

With the older members of our group now, sing along with Tom Lehrer "Be
Prepared -- That's our Boy Scout Marching Song."

Bill Weir
Chair, Committee on Emergency Preparedness, First Unitarian Society of
Minneapolis, MN cell 612-751-0445

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*Simple Interventions May Reduce Transmission of Epidemic Respiratory
Viruses*

Laurie Barclay, MD, September 23, 2009 , Medscape Medical News — Hygiene and
physical measures may effectively reduce transmission of respiratory tract
viruses including influenza, according to the results of a systematic review
reported in the September 23 issue of the *BMJ*.

"Our 2007 Cochrane review showed that physical *interventions (personal
hygiene, barriers, and distancing) are highly effective*," write Tom
Jefferson, MD, from the Acute Respiratory Infections Group, Cochrane
Collaboration, in Rome, Italy, and colleagues. "*However, the current
mainstay of pandemic interventions still seems to be vaccines and antiviral
drugs, with no evidence supporting their widespread use, especially against
a seemingly mild threat such as the novel H1N1 virus.*"

The goal of this review was to assess the evidence for efficacy of physical
interventions to interrupt or decrease the spread of respiratory tract
viruses. The reviewers searched Cochrane Library, Medline, OldMedline,
Embase, and CINAHL for studies published in any language or journal
regarding *any physical intervention to prevent the transmission of
respiratory tract viruses. These interventions included isolation,
quarantine, social distancing, barriers, personal protection, and hygiene.*

Potentially eligible studies included randomized trials, cohort,
case-control, crossover, before-and-after, and time series studies. The
reviewers first scanned the titles, abstracts, and full-text articles and
used a standardized form to determine whether the others were eligible. They
then determined potential bias of randomized trials by evaluating generation
of the allocation sequence, allocation concealment, blinding, and follow-up.
After determination of potential confounders, nonrandomized studies were
categorized as having a low, medium, or high risk for bias.

The reviewers identified 58 articles describing 59 studies eligible for
inclusion. For all 4 randomized controlled trials and most cluster
randomized controlled trials, methodologic quality was poor. The
observational studies were of mixed quality.

*Physical measures were highly effective in the prevention of transmission
of severe acute respiratory syndrome,* according to a meta-analysis of 6
case-control studies. The interventions included the following:

·                                                   *Handwashing more than
10 times daily *(odds ratio [OR], 0.45; 95% confidence interval [CI], 0.36 -
0.57; number needed to treat [NNT], 4; 95% CI, 3.65 - 5.52).

·                                                   *Wearing surgical
masks*(OR, 0.32; 95% CI, 0.25 - 0.40; NNT, 6; 95% CI, 4.54 - 8.03).

·                                                   *Wearing N95 masks* (OR,
0.09; 95% CI, 0.03 - 0.30; NNT, 3; 95% CI, 2.37 - 4.06).

·                                                   *Wearing gloves* (OR,
0.43; 95% CI, 0.29 - 0.65; NNT, 5; 95% CI, 4.15 - 15.41).

·                                                   *Wearing gowns* (OR,
0.23; 95% CI, 0.14 - 0.37; NNT, 5; 95% CI, 3.37 - 7.12).

·                                                   *Handwashing, masks,
gloves, and gowns combined* (OR, 0.09; 95% CI, 0.02 - 0.35; NNT, 3; 95% CI,
2.66 - 4.97).

*The combination of handwashing and use of masks, gloves, and gowns also
effectively interrupted influenza transmission within households. In younger
children and within households, hygienic measures can prevent respiratory
tract virus transmission, according to results from the highest-quality
cluster randomized trials.*

There was limited evidence that the more uncomfortable* and expensive* N95
masks were more effective than simple surgical masks, but they caused skin
irritation.* Any additional benefit of adding virucidals or antiseptics to
normal handwashing was uncertain, and global measures, such as screening at
entry ports, were not properly assessed.

It appeared that social distancing might be effective if used in
relationship to the risk for exposure (the higher the risk, the longer the
distancing period), but evidence was limited.

"Routine long term implementation of some of the measures to interrupt or
reduce the spread of respiratory viruses might be difficult," the review
authors write. "However, many simple and low cost interventions reduce the
transmission of epidemic respiratory viruses. More resources should be
invested into studying which physical interventions are the most effective,
flexible, and cost effective means of minimising the impact of acute
respiratory tract infections."

Limitations of this study include methodologic limitations of the included
studies.

"In situations of high risk of transmission, barrier measures should be
implemented such as wearing gloves, gowns, and masks with a filtration
apparatus, and isolation of likely cases," the study authors conclude. "Most
effort should be concentrated on reducing transmission from young children
through regular education at school on hygiene. In addition, society should
invest in more comfortable* and better designed* face masks and barrier
apparatus, which would increase compliance with their use."

*The National Health Service research and development programme and the
National Health and Medical Research Council of Australia supported this
study. The review authors have disclosed no relevant financial
relationships.* *BMJ*. 2009;339:b3675.

=================================================================================

Comment:  Some of the many types of N95 masks manufactured by 3M and other
companies are quite comfortable and inexpensive.   If you are not carrying
the virus, you can use an N95 mask with a valve that opens only while you
exhale.   Some masks are padded so that there is no skin irritation.  Some
of them can be well fitted over the two very small tubes of a canella
bringing well filtered oxygen from a pressurized bottle or an oxygen
concentrator.  Some effective comfortable N95 masks are priced in quantity
at $1 or less on the web. – Bill Weir 763-568-7022

Do you have any Flu-like Symptoms?



1> High fever (102+), in 80% of H1N1 flu cases,

2> Dry cough,

3> Chest discomfort,

4> Muscle <http://en.wikipedia.org/wiki/Myalgia> pains,

5> Severe headache <http://en.wikipedia.org/wiki/Headache>, in 80%,

6> Weakness and fatigue,

7> Diarrhea

8> Vomiting

9> Chills, in 60%,

10> Pneumonia.

usually with rapid onset, 3-to-6 hours



If you (or someone you are caring for) have any of these, please feel free
to put on one of these respirators, fitting it tightly (without beard or
other hair around rim) so that you breathe out only filtered air.   Until
you do so, you may want to reduce your infecting of others by staying away
-- at least ten feet away.



Please consider calling your primary-care physician or nurse to list your
symptoms, perhaps be seen and ask about a prescription for an anti-viral
(such as Tamiflu).



Please stay out of the assembly at this time.                  *We hope you
are well enough to come next week, *

at least 24 hours after symptoms are gone.

Prepared by Bill Weir, Comte. for Emergency Preparedness, First Unitarian
Society of Minneapolis