• Sheri Greenwell
    340
    Recent changes in advice about suitable types of masks have added even more confusion for workers as well as employers, on top of all the issues with sourcing and supply.

    With NZ government now advising that cloth masks are NOT suitable and everyone should wear approved / verified KN95 or N95 masks, these types of masks are being snapped up quickly and they are not so easy to source at this time. There is also the additional challenge of navigating around scammers and counterfeiters.

    My employer happens to have a number of KN95 masks that (as I understand it) were purchased last year to be able to supply, but were tested fell a little short of the standard so they were quarantined - i.e., these masks apparetnly filtered out only 90% rather than 95%. So the management team is wondering if the organisation could offer these masks to workers as an alternative to single-use surgical masks or cloth masks that would still offer improved protection?

    One part of the business advises "absolutely not, because those masks don't meet the standard and could lead to potential legal issues if someone became infected", while others (including me) think that the organisation could offer these masks if it was done with full transparency about what they are / can do in the way of protection. I would think that 90% would still be a safer alternative than cloth masks, from what I have read?? And at a time when it is difficult to source these masks, this would allow us to offer workers an interim solution that makes sense financially (the 'absolutely not' route would probably see these masks written off).

    Wouldn't it be OK to offer these masks as a reasonable option, accompanied by clear and appropriate communication and instructions and the opportunity for workers to choose?
  • MattD2
    337
    Well if looking at it from a HSWA viewpoint - you're looking to manage the risk "so far as reasonably practicable", with the current options of:
    1. Supply masks that are 90% effective, or
    2. Don't supply masks as there aren't enough supply of N95 masks available (and everyone continue with whatever they have now).

    Seems like your plan would fit into "reasonably practicable".

    I'm interested in the advice to move away from just face covering to respirator (as that is technically what an N95 mask is). My understanding is the main aim for the face covering rules were to reduce the spread of the respirable/aerosol droplets carrying virus from an contagious (but not yet symptomatic) person rather that Personal protection. Anyone got the scientific research backing up the changes in the guidance?
  • Steve H
    308
    Given these masks need to be fit tested to get to the maximum level of protection, is that going to happen Sheri?

    There's a Duke Uni study Matt:

    Duke University study which was published in September 2020, says that correctly fitted N95 masks that cover the full face are the most effective at preventing particle transfer.
  • Chris Anderson
    70
    With NZ government now advising that cloth masks are NOT suitable and everyone should wear approved / verified KN95 or N95 masks, these types of masks are being snapped up quickly and they are not so easy to source at this time.

    The Government has specifically said this is not the case, they have said for those under a vaccine mandate masks must be an actual mask (e.g. 3 ply surgical/ medical mask). They have not mandated P2/ N95 masks specifically due to cost and availability.
  • MattD2
    337
    Duke University study which was published in September 2020, says that correctly fitted N95 masks that cover the full face are the most effective at preventing particle transfer.
    My understanding was the Duke study related to evaluating a simple / cost effective mask testing method rather than specifically the effectiveness of the masks used? While the data on "mask effectiveness" produced during the research is interesting and a possible insight into mask effectiveness, as it wasn't the focus of the study it should be taken with a grain of salt.

    Also while the N95 was "the best", a blue surgical mask was actually pretty close to it. And most other fabric style face masks significantly reduced the detected respirable droplets (<20% of no mask).
    Also to note is that the results provided in the paper (figures below) were based on just a single person using each mask type (except for the hollow circles are an average across 4 people) - so not a sample size that you should draw any specific conclusions from.
    abd3083-f3.jpeg

    A surprising result to me was where the valved N95 sat in the data, around the same reduction as most of the cotton masks.

    But again the purpose of the study wasn't to evaluate masks, it was to evelaute the testing method. The paper's discussion is 100% focused on how the testing method could be improved, and doesn't even mention the eveluation of mask effectvieness at all (except to caution that the results should only serve as a demostration of the testing only). Link to the paper

    My take-away - use face coverings, use the most effective masks available to you that is comfortable enough to allow you to wear it correctly while wearing it. There is no point wearing an N95 if you are going to be constantly taking it on/off to get "fresh air" or end up with it sitting under your nose because you can't breath.
  • MattD2
    337
    Given these masks need to be fit tested to get to the maximum level of protection, is that going to happen Sheri?Steve H
    Let's go back to the beards and respirator thread! ;)
  • Stuart Keer-Keer
    48
    Respirators would be good for the wearer, but if they wearer has covid then they are going to be sharing the love to everyone else. The respirators do not have a filtered outlet.
  • Trudy Downes
    89
    I agree with MattD. Address the risk as is reasonably practicable. How many people are your mask wearers exposed to, under what ventilation circumstances, for how long etc etc. Using your masks in less-risk zones sounds like a fine idea.
  • Sue Nicholson
    2
    We have sourced some masks for our lab workers and postgrad students to minimise the risk of losing all our workforce over our seasonal busy period. They are stated to comply with the FFP2 (EU) standard, and I find them hugely more comfortable and better sealing than cloth masks.
    While it is a 'home project', aerosol scientist Aaron Collins youtube posts give data from his tests on a variety of masks, and advice on fitting.
  • MattD2
    337
    So with the changes to the Covid Protection Framework regarding what counts as an acceptable face covering for each situation I have a question:
    For those that work with workers that are in a vaccine mandated group and are required to wear a "medical-grade face covering", do the masks you have provided your workers meet one of the below standards / criteria (the standards that are listed in the amended Order)?
    • BS EN 14683:2019 - Type IIR
    • ASTM F2100-21 - Level 2
    • AS 4381:2015 - Surprise! The amendment doesn't state which criteria it must pass (but compared to the above I would assume they meant to say Level 2 Barrier)

    Also it is interesting that none of the suggested masks on the MoH guidance for Infection prevention and control recommendations for health and disability care workers webpage seem to have an official certification to any of the standards above (although I would expect that they would likely pass, and the given the wording in the Order technically the masks don't actually have to be certified but just have to be able to pass if they were tested).
  • Andrew
    387
    Latest paper on this issue released by CDC. It is a given mask wearers get covid. So what are the odds of not getting infected if you wear different masks?

    Best mask = N95 type respirators

    Next best = medical masks.

    Odds a bit better than 50/50 (not statistically significant) = cloth masks.

    https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm?s_cid=mm7106e1_w%20%5bcdc.gov%5d#T3_down
  • Sheri Greenwell
    340
    My partner bought us some KN95 masks from the pharmacy. I noted that there were no certifications or markings on the packaging or masks, which he hadn't noticed. After trying without success to find out more about the manufacturer whose details were on the package, he went back to the pharmacy to pick up a prescription and decided to ask the pharmacist about certification. It hadn't occurred to the pharmacist to check certification to the standard......so probably not a genuine KN95.
  • Andrew
    387
    We've all probably got P2's lying around. They are nearly as good as N95's
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