PPE debate continues as expert accuses authorities of following ‘false narratives’

Matt Woodley

18/08/2020 4:43:14 PM

One of Australia’s foremost infectious disease physicians says healthcare workers are being put at undue risk of coronavirus infection by current PPE guidelines.

N95 mask
N95 and P2 respirators are currently only recommended for specific circumstances.

UNSW Global Biosecurity Professor Raina Macintyre believes science related to airborne transmission of coronavirus is being ignored, and Australian healthcare workers are at unnecessary risk of infection as a result.
In a recently-published op-ed, Professor Macintyre said healthcare workers require more protection against the disease.
‘Without proven drugs or vaccines, the precautionary principle should be used to protect healthcare workers from a serious infection such as COVID-19,’ she said.
‘Healthcare workers, like everyone else, are immunologically naïve to this virus but at least 3–4 times at higher risk of infection. The continued denial of scientific evidence of airborne transmission, and shifting goal posts as the evidence accrues, reflects a dogged determination to entrench a position based more on an ideology than science.
‘In the midst of the worst pandemic of our lifetimes, we cannot afford to indulge the reasons for this ideology. Continuing to defend or excuse this ideology imperils the lives of healthcare workers, and distracts from the urgent task of keeping them safe at work.’
Professor Macintyre wrote that current personal protective equipment (PPE) directives are based on ‘very old data’ that suggest large droplets are expelled within two metres and are ‘mutually exclusive’ to smaller particles that linger in the air.
‘In fact, droplets of all sizes exist in a continuum, and large droplets can travel further than two metres,’ Professor Macintyre wrote.
‘Yet this two metre rule defines the safe spatial separation of a patient from a health worker, and informs how health worker risk is determined in the workplace.’
Professor Macintyre told newsGP ‘a respirator is more protective’ than the surgical masks currently being recommended for primary care settings, and that the precautionary principle is ‘warranted to protect all health workers’, including GPs.
Australia’s response to the pandemic has been largely guided by the Infection Control Expert Group (ICEG), which advises the Australian Health Protection Principal Committee (AHPPC) on infection prevention and control issues.
ICEG Chair Professor Lyn Gilbert told newsGP the group has ‘never disputed’ evidence that some respiratory particles produced by people remain in the air for longer than others. However, she says ‘the main source of controversy’ is the clinical and epidemiological significance of these small particles.
‘Strong epidemiological and clinical evidence indicates that the predominant mode of transmission of COVID-19, like most other respiratory viral infections, is by direct transmission of droplets and/or contamination from surfaces and fomites contaminated by these droplets landing on them,’ she said.
‘Protection from COVID-19 depends on a hierarchy of precautions, of which the use of a face covering is one – not necessarily the most important and not adequate on its own.
‘Fresh air or good ventilation, physical distancing or physical barriers, and cough or respiratory and hand hygiene are the most important precautions.’
To support her position, Professor Gilbert pointed to ICEG’s ‘Use of Masks and Respirators in the Context of COVID-19’ paper, published on 26 May.
‘Clinical and epidemiological evidence indicates that COVID-19 is usually transmitted by close contact, in households, enclosed, household-like settings such as residential care facilities, cruise ships and crowded workplaces, where physical distancing is impractical,’ the paper states.
‘In the absence of effective preventive measures, the basic reproductive number [R0] of COVID-19 is 2–3 and the household infection rate is ~10–12%.
‘This contrasts with much higher R0s and household attack rates of infections in which airborne transmission is the rule, including measles [R0,12–18; household attack rate 90%], varicella, [R0 ~10, household attack rate 85%] and tuberculosis.
‘These data suggest that airborne transmission of COVID-19 is infrequent and the routine use of airborne precautions not warranted.’

Professor Raina Macintyre says the argument against airborne transmission is ‘ideological’.
However, in her article Professor Macintyre said health authorities are ‘shifting the goalposts’ of proving airborne transmission, and pointed out viral RNA has been found in air samples taken from hospital wards, as has viable virus.
She also argued against the use of reproductive numbers as evidence to support droplet transmission.
‘This is used as “evidence” that SARS-CoV-2 is not airborne because its R0 is much lower than an airborne virus like measles, which has an R0 of 12–18. However, arguments like this fail to account for other airborne viruses like varicella [which causes chicken pox] that has also been responsible for hospital outbreaks via airborne spread but has an R0 of 4–5, similar to SARS-CoV-2,’ she wrote.
‘Invoking the R0 is a distraction from the science before us. The R0 has never before been a criterion for defining the mode of transmission – in fact, tuberculosis, which is accepted as airborne, has an R0 which is much lower, being <1 in developed countries, than that of SARS-CoV-2.
‘The use of R0 to bolster a failing and implausible argument about transmission of SARS-CoV-2 is disingenuous at worst and ignorant at best.’
GP Dr Kat Mclean, who works at a respiratory clinic in New South Wales, told newsGP she is ‘absolutely’ worried about the prospect of airborne transmission.
‘There’s been concern the whole way through around the guidelines that are out there and certainly it’s something that’s discussed amongst GPs,’ she said.
‘There does seem to be a lack of confidence from GPs who are in respiratory clinics and on the frontline in the PPE that we’ve been given to date.’
Aside from disputing the significance of airborne transmission outside particular circumstances, Professor Gilbert reiterated that respirators – such as N95 or P2 masks – are only effective when fitted to produce a firm seal around the face, which requires training and ‘is not straightforward’.
‘It is for these reasons that ICEG recommends that [respirators] should be used only when they are really needed [eg for aerosol-generating procedures] and only by health workers who are properly trained in their use,’ she said.
‘In other circumstances the best protection of health workers is provided by the full suite of infection control precautions.
‘The risk to health workers cannot be completely removed. COVID-19 is highly transmissible by even minor breaches of infection control precautions, which often occur in the context of heavy workload, stress and tiredness.
‘However, although detailed information about causes of health worker infections are still limited there is growing evidence that a high proportion are due to exposure of health workers in the community or non-clinical settings in the workplace [meeting rooms, tearooms, social gatherings, etc], not due to inadequate PPE provided.’
According to information released by the Department of Health and Human Services (DHHS), 1988 healthcare workers have been infected in Victoria since 16 July, with 1064 of these cases still active. Of these cases, at least two were GPs who ended up in intensive care, and at least one of these is understood to have contracted the virus at a respiratory clinic.
newsGP requested up-to-date statistics regarding the source of healthcare worker infections from the DHHS, but did not receive a response prior to publication.
Previous data, leaked from an 8 August email sent to healthcare workers by Victorian PPE Taskforce Chair Professor Andrew Wilson, indicated that while 21% of cases where the source of infection had been confirmed could be traced back to a healthcare setting (50 out of 237), 87% (1598) were still under investigation.
While Dr Mclean has access to two forms of N95/P2 respirators at her clinic, she feels for colleagues who are not as fortunate.
‘It’s really challenging … I’m yet to be convinced that airborne transmission’s not a possibility and I think whilst that question mark is there, we need to assume that it may well be occurring,’ she said.
‘Given the risk of exposure, and the impact on the GP if you do contract it and become unwell, it to me just seems to be common sense to take a really precautionary approach with it.’
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Dr Lewis Norman Morris   19/08/2020 8:29:28 AM

When is medical research going to cease believing that Epidemiological studies are a gold standard? They may suggest a direction for further research, but that is all. The design of the study is paramount and they heavily rely on statistics. And we all know the flaws of study design and statistics.
A physicist would look at the protection of health care workers from Covid as Professor Macintyre has. So, Covid particles can be transmitted on aerosols, aerosols can travel quite some distance, health workers are subject to increased viral load, and therefore health workers have increased risk of infection and increased severity of illness. To me, QED.

Dr Peter Angus MacIsaac   19/08/2020 9:03:27 AM

So what is this really about -

1. Cost of P2 masks
2. Supply chain and availability
3. Difficulty of addressing best practice in 'fit testing"
4. Lack of a risk management culture accepting that the medical community is justifiably risk adverse.
5. Experts natural inclination to hold on to accepted views somewhat past the time when change should have occurred - what Alvin Toffler called a paradigm shift

Dr Ian Mark Light   19/08/2020 10:32:50 AM

It is optimal to protect the eyes and face if nursing Covid 19 patients which means Face shields and Gowns with face and head protection .
If you cannot get an N95 some advocate a double surgical mask .
Most broadcasts show health workers testing for Covid 19 in the outdoors with gloves gowns head visor and N95 mask or surgical mask .
The great challenge will be severe asthma and exacerbation of COPD when continuing Nebulisation with salbutamol is the treatment of choice with oxygen some asthmatics need 6-8 L per minute .
This is very aerosolising and full body PPE is obligated .
You can attempt MDI inhaler with a spacer but some patients will be so distressed that this will be difficult .
IM Adrenalin or Subcutaneous Salbutamol might be needed if you cannot nebulise.
The WHO did declare that crowded indoor Spaces with suboptimal fresh air exchange is deleterious after 239 scientists wrote the open letter to WHO about the small droplet -airborne spread danger with Covid 19 .