In mitigating the occupational threat of Covid-19 in Irish healthcare, is the HSE behind the curve in integrating the expertise of occupational hygiene and other applied sciences? Catherine Reilly reports
“In general terms the medical profession – other than those who are occupational health physicians – do not understand the discipline of occupational hygiene,” a health and safety expert, working in private practice, tells the Medical Independent (MI). “They think that it is cleaning. They don’t see it and they don’t value it.”
Through science and engineering, occupational hygienists identify, evaluate, and control exposure to workplace hazards including biological and chemical agents.
In Ireland, occupational hygienists work in a range of sectors, such as pharmaceuticals, where they mitigate the risks to employees of exposure to active pharmaceutical ingredients and other potential harms. However, despite the HSE being the largest employer in the State, and operating a wide range of functions, the role is not even referenced in its extensive list of staff grades.
Periodically, occupational hygienists are contracted by healthcare facilities for specific exercises, eg, monitoring exposure to chemicals to ensure compliance with the occupational exposure limit value under regulations.
During the Covid-19 pandemic, occupational hygiene bodies internationally have urged healthcare systems to rigorously apply established measures of exposure control to protect healthcare workers from SARS-CoV-2 infection. In this regard, they have emphasised that all potential transmission routes must be addressed – including by means of inhaled aerosols (not limited to aerosol-generating procedures-AGPs).
Surgical masks do not provide adequate protection to the wearer in circumstances where personal protective equipment (PPE) is deemed necessary as part of a hierarchy of control measures in healthcare, they have warned.
A paper published in Occupational Medicine in late April 2020, titled ‘Protecting healthcare workers from inhaled SARS-CoV-2 virus’, noted studies that “strongly indicate that the virus may be present in the air in hospitals and it is known that the aerosol may remain infective for a period of hours”. There were many uncertainties, such as how the concentration differed in various situations and the inhaled dose required to cause infection.
The authors from the Institute of Occupational Medicine (IOM), UK, urged a precautionary approach and adoption of “good occupational hygiene principles”.
They emphasised the importance of designing and operating activities to minimise the emission, release and spread of the virus. Where PPE was necessary, they cautioned that surgical masks were not an adequate form of protection compared to filtering facepiece respirators, such as the FFP3 mask, for those working in health and social care settings.
Furthermore, healthcare workers undertaking AGPs should be provided with and trained to use reusable powered air-purifying respirators.
Last month, co-author of the paper, Prof John Cherrie, Principal Scientist at the IOM and Professor of Human Health at Heriot Watt University, UK, told MI “it took a while for the message to get any traction” and the official view “is still that the level of PPE [we] would prefer to see available is not required”.
He believed there had been “little involvement of hygienists in the NHS response at a policy level – in fact, occupational health as a whole seems to have been sidelined”.
Evidence of the airborne risk in clinical settings is accumulating. A recent study in Open Forum Infectious Diseases by clinicians at Schneider Children’s Medical Centre of Israel described an outbreak of SARS-CoV-2 nosocomial infections despite using surgical masks and physical distancing. AGPs were not reported as a factor in this outbreak.
Concerns over HSE infection prevention and control (IPC) guidance have been raised with the Executive by some occupational medicine specialists, who also say their departments have been sparsely resourced and insufficiently empowered.
One specialist pointed to studies from the SARS-CoV-1 and MERS-CoV outbreaks, and on the influenza virus, which demonstrated the inadequacy of surgical masks as a protection to the wearer against airborne – and droplet – exposure.
“But they are being used for worker protection here, which they are not effective for.”
The biological agents regulations require employers to apply prevention and risk reduction measures to ensure that, as far as technically practicable, the level of exposure of employees is reduced to “as low a level as necessary” in order to adequately protect their health and safety.
The specialist said overall control measures had not been adequately employed in healthcare.
“The evidence around the efficacy of ventilation, masks, eliminating the hazard and then putting in engineering controls between the source of the hazard and the people exposed – and what constitutes effective protective equipment – have not been properly considered.”
From early in the pandemic, the specialist advised that a precautionary approach in healthcare facilities should have been adopted, including fitted FFP2/FFP3 masks for close patient care.
The specialist said healthcare professionals engaged in AGPs/high-risk areas should be wearing powered air-purifying respirators (PAPRs) (the national guidance has recommended FFP2 masks).
Some consultants had bought their own PAPR “because the organisation is not responding with its health and safety management systems to implement a safe, managed work environment against Covid”.
The specialist urged greater involvement of occupational medicine in devising IPC guidance, and that the input of disciplines such as occupational hygiene, exposure science, and aerosol engineering, be included.
Unlike in the initial stages of the pandemic, testing capacity is now established and developed. This must be maintained and applied strategically “in spite of vaccination to identify and break chains of transmission, especially of new variants”, added the specialist.
As of the third week in January 2021, some 22,484 cases of Covid-19 in healthcare workers had been notified to the Health Protection Surveillance Centre (HPSC), representing 12 per cent of the 188,129 notified cases. Some 744 healthcare workers had been hospitalised, 76 admitted to intensive care, and 12 had died.
Reported Covid-19 cases in healthcare workers are not all workplace-acquired. However, their infection risk is much higher compared to the general community. The ‘Prevalence of Antibodies to SARS-CoV-2 in Irish Healthcare Workers’ (PRECISE) study recently reported that seroprevalence in healthcare staff at St James’s Hospital, Dublin, and University Hospital Galway, was six-times that of community seroprevalence in each geo-area.
At St James’s, one-in-five frontline healthcare workers who cared for patients with confirmed or suspected Covid-19 had SARS-CoV-2 antibodies.
MI asked the HSE whether the input of its National Health and Safety Function, which has specialist expertise in health and safety, was included in the process of developing Covid-19 national IPC and PPE guidance, and whether the Function had issued relevant findings on this area following audits or inspections during the pandemic.
Information was also sought on the number of health and safety professionals – including occupational hygienists – employed by the HSE. A response was awaited at press time.
National IPC and PPE guidance is largely devised within the Antimicrobial Resistance and Infection Control (AMRIC) Division, HPSC. This division has significant clinical expertise and experience in the prevention and control of established healthcare-associated infections in a pressurised system with high bed occupancy and many antiquated wards and buildings.
It has been pivotal, for example, in bringing some control to the escalating spread of carbapenemase-producing Enterobacterales in healthcare, which was declared a national public health emergency in 2017.
An expert advisory group to the Covid-19 national public health emergency team (NPHET) has also influenced IPC and PPE guidance in the pandemic. It issued a recommendation for routine surgical masking for healthcare workers in April after several weeks of debate. Respiratory protective equipment (RPE) was recommended only for AGPs in national guidance, but this has been recently updated.
The HPSC guidance for Covid-19 has been based on an assessment that SARS-CoV-2 is “in most circumstances” a contact and droplet transmitted infection and “the evidence that surgical masks offer equivalent protection to respirator masks in this context”, the HSE informed MI in November 2020. Mask wearing was “only one element” of the IPC precautions required, it also emphasised.
In recent weeks, the HSE has decided to mandate wider deployment of FFP2 masks in clinical areas. This followed pressure from the Irish Nurses and Midwives Organisation (INMO), which expressed concern about the emergence of more transmissible variants and escalating outbreaks in healthcare settings. The INMO has also called for the distance between beds to be increased from one metre minimum to two metres, rolling testing for all staff, and a safety review in each hospital.
A spokesperson for the Health and Safety Authority (HSA) said NPHET, its expert subgroups and the HSE HPSC, provide “a significant level of infection prevention and control advice and general approaches to managing the suppression of the virus within a healthcare setting”.
The guidance for healthcare settings covers a range of precautions to address spread of the virus “via contact and droplet transmission” including the use of PPE.
“The HSA have engaged with the HSE, along with other employers and employee representative groups in the sector and we will continue to engage with them. Healthcare workers caring for Covid-19/suspected Covid-19 patients should have access to PPE including respirator masks.”
The HPSC “continue to update their guidance in line with the emerging evidence”, they added.
The Authority confirmed it is aware of reports of a number of healthcare workers who have died with Covid-19. “We have commenced initial enquiries into these reports to ascertain the relevant facts.”
Redrawing the traditional paradigms of IPC guidance development, in the face of a novel respiratory pathogen, has been advocated by the British Occupational Hygiene Society (BOHS). It is one of the world’s foremost occupational hygiene bodies and its Faculty of Occupational Hygiene has 36 members in the Republic of Ireland.
Speaking to MI, President-Elect of the BOHS, Ms Alison Margary, said occupational hygiene is not part of the core governance of occupational health risks in UK hospitals. This is an alarming oversight, she said, particularly in the context of the Covid-19 pandemic.
“Occupational hygienists were not properly engaged in pandemic planning – this was startlingly clear not only with the PPE problems, but also in the lack of consideration to other important forms of control.” It was an “opportunity missed”, according to Ms Margary.
She said the Society was aware of “a handful” of occupational hygienists employed by the NHS in England and Wales.
“Typically, the NHS employs general health and safety advisors to carry out general workplace risk assessments and they may call on an occupational hygienist in a consulting capacity, to investigate specific health hazards such as exposure to anaesthetic gases, for example.”
Ms Margary explained that occupational hygienists are focused on prevention and have technical expertise in identifying and assessing health risks and recommending control measures according to a hierarchy. This involves seeking to eliminate or substitute the hazard first, progressing to engineering and administrative controls, before considering the use of PPE as the last line of defence, to mitigate exposure to hazardous agents such as SARS-CoV-2.
“We are trained to track down and investigate all potential sources of health risk in a systematic way to come with a complete picture on which to formulate control strategies,” she said of the general approach of occupational hygienists.
“We saw first-hand in the early stage of the pandemic how the implementation of control for healthcare workers at the frontline was reactive; as hygienists we looked on in horror to see what was going on – nurses and doctors wearing inappropriate respiratory protection, which was all over the news in the early days, or if they were wearing appropriate protection, they were not wearing it correctly in many cases.
“We also noticed the key reliance on PPE, which raised alarm bells as we know PPE is not a robust method of control and typically should only be used as a secondary line of defence, with focus given to engineering controls, like ventilation, and administrative controls such as segregation, distancing and disinfection.” Ms Margary was also critical of the provision of surgical masks to healthcare workers under a premise of “providing protection to the wearer”.
While PPE is a necessary control measure for frontline healthcare workers during the pandemic, it is important to recognise that it can breed a false sense of security.
Additionally, Ms Margary underlined that fit testing for respirator masks is of paramount importance. In Ireland, inspections by the HSA have identified a lack of fit testing in healthcare facilities. The health and safety expert, referenced at the start of the article, said that use of respirator masks in Irish healthcare was limited until the Covid-19 pandemic: “Consequently, they didn’t anticipate all the hassle that goes with them.”
RPE programmes are labour intensive, but necessary to address the residual risk of a biological hazard when other control measures are not sufficient, this expert added.
In the early stages of the pandemic, the UK Health and Safety Executive requested that the NHS seek the expert input of occupational hygienists on implementing RPE programmes.
“There was uncertainty [in hospitals] about the difference between quantitative versus qualitative testing of fit; type of respirators; and their effectiveness,” explained Ms Margary. “We all know it is easy to put on a mask, but it is another matter to be issued with a respirator that fits, checked that it is a good fit, and worn correctly for as long as needed, because everybody has different shaped faces and they can be uncomfortable to wear over long periods, causing sweating leading to skin irritation and aggravating fatigue.”
Traditionally, the focus of IPC in hospital settings has been on patient safety. But the pandemic has underscored that hospitals are “quite complex workplaces” where clinical and non-clinical staff are exposed to different types of infection risks. “The focus of hospital infection prevention has been the patient safety aspect, rather than considering the workforce health protection as a whole,” she noted.
“Of course, normally this would not be a problem, it would be a sound strategy, because your respiratory infection risk would arise from exposure to a few patients in a controlled clinical environment. But in a pandemic, fellow workers like delivery drivers, contractors, caterers, hospital visitors, all pose an infection risk,” she said, adding that the workplace itself becomes a focus of risk.
For occupational hygienists, this type of scenario is their “bread and butter” and they would take a systematic approach to the workplace risk.
A positive aspect of the pandemic has been greater inter-disciplinary dialogue and communication.
The BOHS is participating in an occupational health forum involving occupational health physicians and nurses, psychologists, occupational therapists, and ergonomists, among others representing their professional organisations, including the Society of Occupational Medicine and Faculty of Occupational Medicine (UK). This forum has linked with IPC clinicians, as well as the Health and Safety Executive.
“We cannot say for sure yet whether the NHS or Public Health England will be approaching us to say ‘we need your expertise in our core planning teams’. But we certainly are going to continue to push,” commented Ms Margary.
‘Excellent employability rate’
For decades, occupational hygienists have been working with occupational medicine in the workplace, managing hazard and exposure assessment programmes across many sectors, according to Dr Marie Coggins, Lecturer in Exposure Science at the School of Physics, NUI Galway, and Programme Director of the university’s BSc in Environmental Health and Safety.
Occupational hygiene is taught during third and fourth year of the BSc in Environmental Health and Safety, a programme accredited by the Institution of Occupational Safety and Health (IOSH) in the UK. The university’s postgraduate programmes in Occupational and Environmental Health and Safety are accredited by both the IOSH and the BOHS.
“That means graduates of our programme are recognised by the BOHS and they can apply to the BOHS to obtain a professional qualification in occupational hygiene,” said Dr Coggins.
Graduates have an “excellent employability rate” and predominantly work in the pharmaceutical, medical device, manufacturing, healthcare, food, construction, and regulatory sectors.
Dr Coggins said occupational hygienists have specialist skills in exposure assessment and control and risk management, particularly in the selection and correct use of PPE, including RPE, which is especially relevant in the Covid-19 pandemic.
“They also have expertise in translating complex regulatory/scientific knowledge into operational workplace procedures for workers and managers,” she outlined.
Echoing points made by professional colleagues, Dr Coggins advised that a Covid-19 control strategy needs to address all possible routes of exposure – contact, droplet, and airborne. On the latter route, she said there have been many Covid-19 outbreaks internationally that implicate the aerosol transmission pathway.
She noted that when controlling exposure to a hazardous agent in the workplace, it is important to consider the hierarchy of control options. If PPE is required, its selection, fit and training on its use, are key to its effectiveness.
PAPRs and filtering face pieces, such as FFP2/FFP3 masks, are often recommended for high-risk aerosol generating tasks. Surgical face masks provide a much lower protection factor than PAPRs or FFPs and were originally designed to limit outward leakage of aerosols, Dr Coggins outlined.
When assigning respirator masks, a respirator fit test should be part of the selection process. An incorrect fit could lead to contact transmission, as the wearer fidgets with the mask to try and get it to sit better on the face.
Dr Coggins added that the BOHS has published a guidance document titled ‘Covid-19 Occupational Risk Rating and Control Options according to Exposure Ranking’. She advised that this document is “an excellent guide” for managers in any sector tasked with the selection of exposure controls.
The guidance document is available at COVID-19 Hub – British Occupational Hygiene Society (BOHS)
‘Very poor understanding’ of inadequate ventilation risks – architect
Insufficient warnings on airborne transmission of SARS-CoV-2 and the high risk posed by poorly ventilated settings represent “a really major misstep in policy”, states Ms Orla Hegarty, Lecturer and Assistant Professor, School of Architecture, Planning and Environmental Policy, University College Dublin. Ms Hegarty also lectures on building regulations and health and safety in construction.
Globally, the role of airborne or aerosol transmission of SARS-CoV-2 continues to be the subject of intense debate in the medical and scientific community.
A letter published in Clinical Infectious Diseases in July 2020, which was endorsed by 239 scientific and medical experts, advised that studies by the signatories and other scientists had demonstrated “beyond any reasonable doubt” that viruses are released during exhalation, talking, and coughing in microdroplets small enough to remain aloft in air and “pose a risk of exposure at distances beyond 1–2m from an infected individual”.
The signatories urged the World Health Organisation (WHO) to issue appropriate warnings about the risks posed by aerosols and adopt precautionary principles. The WHO states that “current evidence suggests that the main way the virus spreads is by respiratory droplets among people who are in close contact with each other”. Airborne transmission “can occur in specific settings, particularly in indoor, crowded and inadequately ventilated spaces”.
The HSE says airborne transmission “can happen in some situations” and advises that indoor spaces are kept well ventilated.
In Ireland and abroad, inconsistencies have been highlighted in the level of public health messaging applied to potential fomite transmission in comparison to airborne transmission. The WHO has acknowledged a lack of evidence demonstrating fomite transmission of SARS-CoV-2, although surface contamination is documented.
Ms Hegarty noted that, in the autumn, the HSE public health advice incorporated “some references to Covid being airborne but indirectly and inconsistently”. She considers that airborne transmission has been driving the pandemic.
There has been “very poor understanding” within both the public and healthcare spheres about the risk of airborne transmission, she underlined.
“Whether that has been driven by a lack of understanding of all of the scientific research that has gone on in the last 10 months, whether it has been driven by concerns about a perceived cost of changing buildings or supply of PPE or whether it is being influenced by the economic objectives to maintain sectors such as hospitality and air travel, is not clear; but fundamentally the shared objectives of saving lives and livelihoods can only be achieved with an evidence-led and collaborative approach.”
She added: “There have been some concerns that the composition of NPHET for the initial emergency response has been slow to expand to a more strategic approach because it started predominantly with people of a medical background. It is now engaging environmental expertise. Given that the spread of the virus is environmental, this is critical to targeted prevention and careful evidence-led reopening.”
Ms Hegarty said a lack of clarity led people into “very dangerous conditions” such as indoor dining and gatherings at Christmas, “without taking precautions for airborne spread.”
Long-term care and hospital buildings
In November 2020, Ms Hegarty wrote a paper titled ‘Covid-19 Risks in Nursing Homes and Prevention Strategies’, which outlined low-cost prevention and mitigation measures to reduce the risks posed by poor ventilation and particular winter conditions of low humidity.
According to Ms Hegarty, all buildings need to be monitored for these high-risk conditions, and some need to be independently inspected by an architect or engineer.
However, in the short-term, she recommended purging ventilation at intervals to disperse the virus with regular ‘airing out’ of rooms; improving background ventilation to dilute the virus and keep air moving (windows slightly open, doors open for cross ventilation, etc); ensuring wall vents are not blocked and kept open; increasing humidity with humidifiers and/or bowls of water for evaporation; monitoring poor ventilation and low humidity with CO2 (carbon dioxide monitors) to keep CO2 below 600ppm, as CO2 build-up is a proxy for inadequate ventilation; using portable filtration fans to ‘clean’ the air; wearing well-fitting masks.
The paper urged awareness raising about high-risk conditions and prevention measures.
Ms Hegarty said there is still a prevailing narrative of the virus “getting in” to nursing homes.
“It has been ‘getting in’ to buildings since last March, but it only catches hold in certain environmental conditions. We said we had a very low rate [of community transmission] for example in August, and yet it ‘got in’ to the meat plants and there were large outbreaks.
“Meat plant super-spread has happened in many countries due to recirculation of cold, dry air and it can be mitigated by changing operation of the ventilation. When the weather got colder and the nursing homes closed the windows and turned up the heat it ‘got in’… again”
The infrastructure and décor of many nursing homes – in converted or extended buildings perhaps with internal corridors, blocked vents, closed double-glazed windows, heavy curtains and draught proofing – generate risky conditions.
Ms Hegarty has had cause to visit hospitals in recent months and noted healthcare workers who are very diligent about infection control procedures but with “poor understanding about the actual
risk and the mechanisms of transmission”.
“If I was doing a risk assessment on a hospital, I would immediately identify times when people are not wearing masks as very high-risk – toilets, changing rooms, storerooms, break rooms, and you would say, how do we mitigate the risk of breaks? Do we put up a marquee, do we ask people to eat in their cars, do we section off part of the multi-storey car park, which is open to the air, and put in tables and patio heaters?”
Older hospitals that have had energy upgrades or been subdivided may be more susceptible to outbreaks, she added.
“There may also be poor ventilation in prefab extensions, such as temporary buildings for outpatients and emergency departments with low ceilings and small windows.
“Some of these may also be heated with systems that dry out the air as well. In these environments low humidity is a known risk for airborne spread.”
But these types of issues are “all solvable” if the risk is acknowledged, and many can be mitigated quickly, often at no cost, emphasised Ms Hegarty.
MI understands a new expert group on ventilation has recently formed under the NPHET