WHO and masks

[HeresMe]

Part of the problem is they keep changing minds on things.

I can understand need to be consistent but their flipfloping is silly.

Yes it is a evolving situation but it isn't the first coronavirus they have encountered or airborne respiratory illness either.

With their early efforts to play politics with China I'm very wary of the WHO. And before anyone starts trump accusing he's a dick.

I don’t suppose they are all that worried what you think of them to be fair.

I'm not worried what you think so there you go.

WHO base their guidance on all the evidence available. This may not be the first coronavirus but it's the first large scale pandemic coronavirus and it's generating an absolute fuckton of research. In a recent press briefing they said they were reviewing around 600 new papers on covid-19 every day, of extremely variable quality, many of which are contradictory.

Their new guidance on the use of masks by children is available here (scroll to the bottom of the page):

www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks

They make clear that:

• this guidance is an annexe to their more general advice on masks and face coverings (also available at the link above). There has been no 'flipfloping'.

• this guidance is not based on any new, strong evidence, but on the consensus of several large panels of world experts.

• this is interim guidance that will likely change as more evidence becomes available. If there is no new evidence in the next six months, this guidance will expire.

They say the overarching guiding principles for policy makers should be:

• Do no harm: the best interest, health and well-being of the child should be prioritized.

• The guidance should not negatively impact development and learning outcomes.

• The guidance should consider the feasibility of implementing recommendations in different social, cultural and geographic contexts, including settings with limited resources, humanitarian settings and among children with disabilities or specific health conditions.

I've only had time to skim it but it looks good to me. I'm particularly pleased that they have strongly advised against face coverings for children under 5.

Basically, the whole world wants to know what to do about children and masks, so WHO has released interim guidance saying, 'We don't have much evidence, this is what the experts currently reckon and it's our best guess at a sensible policy for the time being. If there's new evidence in the next 6 months we'll review this guidance. If there isn't, we'll bin it.

If they didn't release any guidance at all, people would slam them for that. They can't win.

With their early efforts to play politics with China I'm very wary of the WHO.

What do you think they should or could have done differently?

@HeresMe

Part of the problem is they keep changing minds on things.

I can understand need to be consistent but their flipfloping is silly.

Yes it is a evolving situation but it isn't the first coronavirus they have encountered or airborne respiratory illness either.

With their early efforts to play politics with China I'm very wary of the WHO. And before anyone starts trump accusing he's a dick.

I agree too much up china bum and lied

Same question to you, Ellsbells12 - What do you think they should or could have done differently?

Also, what lies did they tell?

What do you think they lied about @

That was meant to be Ellsbells12

They should have advocated for masks earlier. They must have known masks helped prevent transmission, it's just basic common sense but instead they sent out confusing messages about how masks must be:

1. Not used by the public as they're ineffective but also

1. Must be saved for healthcare workers as they are essential and effective

Just doesn't make sense.

@LangClegsInSpace

Thanks for the link. It’s good to get confirmation that there isn’t any new evidence or ‘the science’, but rather the push for face coverings is based on opinion rather than fact.

this guidance is not based on any new, strong evidence, but on the consensus of several large panels of world experts.

To make sense of WHO guidance you need to bear in mind the difference between medical masks and cloth face coverings/other non-medical face coverings, and the difference between PPE (protects the wearer) and source control (protects others).

WHO produced interim guidance on PPE in medical settings on 6 April. Most of the guidance was about what type of PPE health care workers should be wearing in various settings, how to manage supply and what to do if you ran out. They said:

• cloth face coverings are not effective as PPE (i.e. protects the wearer) in medical settings.

• medical masks should not be used by the general public because there was a global shortage and medical grade PPE was needed by frontline staff.

• medical masks should be worn by people with symptoms being cared for at home, as a form of source control (i.e. protects others).

They made no recommendations on cloth face coverings worn by the general public as source control because there was not enough evidence.

WHO produced further interim guidance on 5 June which incorporated further evidence on transmission, continuous use of medical masks as PPE by health care workers in areas of community transmission, and new advice on the use of cloth face coverings by the general public, as a method of source control. They said:

• medical masks should be worn continuously, as PPE, by health care staff in contact with patients, in areas of community transmission, where there are adequate supplies. This recommendation was based on a systematic review of observational studies during SARS and MERS outbreaks.

• cloth face coverings are not effective as PPE (i.e. protects the wearer) in medical settings - reiterating previous advice.

• medical masks should be worn by people with symptoms being cared for at home, as a form of source control (i.e. protects others) - reiterating previous advice.

• cloth face coverings have a potential benefit for source control, in areas of community transmission, in situations where social distancing is not possible or where population density is very high, e.g. refugee camps. This is based on a meta-analysis of observational studies of the use of medical masks or 12-16 layer (!) cotton masks in outbreaks of other respiratory diseases. They were clear in the guidance that there is no strong, direct evidence for the effectiveness of widespread non-medical mask wearing by healthy people in the community. I believe there have been other observational studies since the beginning of June that have shown some benefit.

• where there are adequate supplies, medical masks should be worn by over 60's and those with underlying conditions in situations where there is community transmission and social distancing is not possible, as PPE and not as potential source control.

• medical masks should not be used by the rest of the general public but should be reserved for frontline staff - reiteration of previous advice.

They make recommendations for the construction of cloth masks based on the French AFNOR group standards, which take into account both the breathability and filtering ability of various combinations of materials.

They say governments that want to introduce a policy on cloth face coverings should take a risk based approach, looking at both potential benefits and disadvantages and should take account of local infection rates and other circumstances.

They say WHO encourages countries and community adopting policies on masks use in the general public to conduct good quality research to assess the effectiveness of this intervention to prevent and control transmission.

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I think WHO have been clear throughout their guidance that there is no strong evidence for the widespread use of non-medical face coverings by the general public but that they might help a bit in certain circumstances. When you read the actual guidance documents they are very nuanced.

I don't want WHO producing guidance based on 'common sense', I want their guidance to be based on the best available evidence, even if that results in them saying, 'there is only weak, indirect evidence for this measure. If you're going to do it, here is what to bear in mind, and can you please do some research while you're at it so we can in turn improve our guidance.'

Wear a mask to protect yourself

m.youtube.com/user/Campbellteaching

Published on Sep 1, 2020

All referenced hyperlinked below for personal perusal and verification. CDC

www.cdc.gov/coronavirus/2019-...

Masks reduce the spray of droplets when worn over the nose and mouth

Prevent people who have COVID-19 from spreading virus to others

Respiratory virus shedding in exhaled breath and efficacy of face masks (Nature Medicine)

www.nature.com/articles/s4159...

Aerosol transmission is a potential mode of transmission for coronaviruses as well as influenza viruses and rhinoviruses

Universal use of face masks for success against COVID-19: evidence and implications for prevention policies (European Respiratory Journal)

erj.ersjournals.com/content/5...

Cloth masks are a simple, economic and sustainable alternative to surgical masks as a means of source control of SARS-CoV-2 in the general community

Mask wearers are dramatically less likely to get a severe case of Covid-19

www.inverse.com/mind-body/mas...

Professor Monica Gandhi, San Francisco General Hospital.

No mask is perfect

Wearing one might not prevent you from getting infected

But it might be the difference between a case of Covid-19 that sends you to the hospital and a case so mild you don’t even realize you’re infected.

Masks Do More Than Protect Others During COVID-19: Reducing the Inoculum of SARS-CoV-2 to Protect the Wearer (Journal of General Internal Medicine)

link.springer.com/article/10....

Universal masking reduces the “inoculum”

Leading to more mild and asymptomatic infection manifestations

Masks, depending on type, filter out the majority of viral particles, but not all

Viral inoculum and severity of disease (LD50)

Rising rates of asymptomatic infection with population-level masking

Increased with mask wearing, decreased where few masks are worn

So, more asymptomatic infections

Greater community-level immunity and slower spread

Cloth Masks May Prevent Transmission of COVID-19: An Evidence-Based, Risk-Based Approach (Annals of Internal Medicine)

www.acpjournals.org/doi/10.73...

The point is not that some particles can penetrate but that some particles are stopped

Every virus-laden particle retained in a mask is not available to hang in the air as an aerosol or fall to a surface to be later picked up by touch.

Cloth can block droplets and aerosols, and layers add efficiency.

Immunity and immunopathology to viruses: what decides the outcome? (Nature, Reviews Immunology)

www.nature.com/articles/nri2802

The outcome of host–viral interactions depend on

Dose and route of infection

Viral virulence properties

Several host factors that mainly involve innate and adaptive immunity

If the exposure dose is very high, the immune response can become overwhelmed.

If the initial dose of the virus is small, the immune system is able to contain the virus with less drastic measures.

If this happens, fewer symptoms, if any

A simple method of estimating fifty per cent end points, (American Journal of Hygiene, 1938)

academic.oup.com/aje/article-...

Viral dose being related to disease severity

Validation of the Wild-type Influenza A Human Challenge Model H1N1pdMIST: An A(H1N1)pdm09 Dose-Finding Investigational New Drug Study (Clinical Infectious Diseases)

academic.oup.com/cid/article/...

Clinical symptoms of influenza occurred at all doses (Table 1), but were most prevalent at 106 and 107 TCID (tissue culture infectious dose)

Higher viral doses, the more sick people became

Simple Respiratory Protection—Evaluation of the Filtration Performance of Cloth Masks and Common Fabric Materials Against 20–1000 nm Size Particles, (The Annals of Occupational Hygiene)

academic.oup.com/annweh/artic...

Masks increase the rate of asymptomatic cases, (Annals of Internal Medicine)

www.cdc.gov/coronavirus/2019-...

theconversation.com/can-peopl...

www.acpjournals.org/doi/10.73...

COVID-19: in the footsteps of Ernest Shackleton, (MBJ, Thorax)

thorax.bmj.com/content/75/8/693

Cases at seafood plant cause spike in Oregon COVID numbers (Pacific Seafoods)

apnews.com/4b9d38f206db9ce526...

Releases Covid-19 Test Results at Northwest Arkansas Facilities (Tyson)

www.tysonfoods.com/news/news-...