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GP invests thousands in air filtration to curb COVID transmission
Dr Bernard Shiu sees the investment as a ‘community service’ to protect his staff and patients. Now he is advocating for more guidance and support from Government.
Dr Bernard Shiu has purchased eight HEPA filters for his Geelong practice, costing him more than $3000. (Image: Supplied)
Since the rapid spread of the Omicron variant, Dr Bernard Shiu is among a growing number of practice owners digging deep to invest in air filtration systems for their practice.
The Geelong GP recently purchased eight high-efficiency particulate air (HEPA) filters to improve the air quality throughout his practice – enough to have one in every practice room, including the staff room and reception – with each filter setting him back $400.
Dr Shiu told newsGP he had been looking into alternative ways to keep his staff and patients safe for some time, and in the absence of official guidance decided to look into existing evidence and organise an environmental engineer to assess his practice and measure carbon dioxide (CO2) levels.
‘I started looking into different ways of purifying the air, all the way to using UV light and humidified hydrogen peroxide to ways of doing a negative pressure room with unidirectional airflow ventilation, but found out it was going to cost $17,000 per room to make it happen – there’s no way that any general practice will be able to afford that,’ he said.
Guided by research from Melbourne University, and an official recommendation for general practices in the UK on the use of HEPA filters, Dr Shiu decided it would be the best alternative.
The role of aerosol spread in COVID-19 transmission has been a contested issue during the pandemic.
Despite calls from experts, it wasn’t until May 2021 – 16 months after COVID emerged – that the World Health Organization (WHO) formally recognised the role airborne transmission has in spreading the virus.
And while Australia’s Infection Control Expert Group (ICEG) acknowledged the role of aerosol spread ahead of the WHO in October 2020, it wasn’t until June 2021 that its PPE guidance on the need for N95/P2 respirators was updated.
Professor Ben Mullins from Curtin University, who is an expert on aerosol spread, filtration and ventilation systems, said he was surprised by the debate – an issue he attributes in part to a ‘completely arbitrary and fictitious’ distinction that has been set on the behaviour of aerosols and droplets.
‘Everything in air is an aerosol, regardless of size, and whether it’s slightly above or slightly below five microns, there’s very little difference in the behaviour,’ he told newsGP.
‘So it highlighted that we’ve imposed this artificial limit, which we probably should remove.’
Research has shown that particles less than five microns can remain suspended in the air for several hours, and that a HEPA filter can remove 99.9% of aerosolised virus particles in the air.
According to Professor Mullins, the challenge with conventional buildings is that they usually have a Heating, Ventilation and Air Conditioning (HVAC) system designed to only filter incoming air based on moderate levels of occupancy, and to filter that air only once.
In these cases, natural ventilation, such as opening windows, can be very effective at diluting any air that may be contaminated by a virus, such as SARS-CoV-2. However, with many modern clinics having a cubicle set-up with no windows, Professor Mullins says air purifiers ‘definitely have an important role to play’.
‘There are several studies now that have shown that they can significantly reduce the aerosol and viral loads in indoor settings,’ he said.
‘The idea of these air purifiers or internal HEPA filters are essentially a pump or a fan or a filter so the air within the room is continually cycled around and filtered.
‘Even if you have a fairly poor filter, it doesn’t necessarily have to be a HEPA filter, you will get improved air quality in the room just by the fact that you’re filtering this air multiple times.’
However, Professor Mullins also points out it is important to be mindful of airflow in close contact situations.
While air purifiers can be strategically placed, he says they are unlikely to be very effective in a scenario where the GP is assessing the patient in close range or conducting a procedure.
‘Those are settings where the clinician wearing PPE is the utmost importance [and] obviously minimising contact with the patient and doing whatever pre-screening you can to make sure they don’t have COVID before you have any close clinical contact,’ Professor Mullins said.
‘Air purifiers are probably most effective in waiting rooms or where people are congregating to make sure that if you have a COVID-positive patient walk in, even if they’re not seen clinically, then that might stop them from passing on that infection to other patients or administrative staff.’
Dr Shiu’s practice now has an air filtration unit in every consultation room.
Though he recognises that it is just one part of the defence against COVID-19 transmission, almost two years into the pandemic he believes it is time general practices receive official recommendations on their use from government authorities.
‘I would appreciate some official guidelines … to say how big of a room and how big of a filter it’s going to need,’ he said.
‘I had to figure that out myself by doing the measurements, doing the testing and doing my own research. Other practices may not have the facilities or the capacity to do that.’
And with governments
having recognised the benefit of filtration units and planning to fit out schools ahead of Term 1, Dr Shiu says funding is the vital next step.
According to Professor Mullins, the immediate the cost of retrofitting older facilities would be a significant burden, as there is no one size fits all approach. However, he agrees funding is needed.
‘There are consultants who would be able to advise on these sorts of things, so funding for a scheme to provide the best solution to each individual practice might be a useful option,’ he said.
Dr Shiu says governments should be willing to provide that funding, especially as they continue to recognise general practice’s vital role in keeping patients out of hospitals.
‘The only way that we can do that is if we keep the staff safe and healthy – and that’s exactly what we’re trying to do,’ he said.
‘It is an investment into the community, into our staff, and into our clinics as a whole.’
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