Human challenge studies in the study of infectious diseases
What can deliberately infecting healthy people tell us about infectious diseases? How is this useful for developing treatments, and how do we manage the risks?
Some occupational groups have experienced higher rates of both COVID-19 infections and related deaths. Many people who work within these groups are involved in caring for people or patients that are more likely to be infected, or have otherwise been unable to work from home during the peaks of transmission. Which occupations have been most affected, what factors are contributing to this risk and are some sectors of the population being impacted more than others?
DOI: https://doi.org/10.58248/RR07
Occupational risks refer to the probability of injury or illness occurring as a result of hazards within the workplace. These can include (but are not limited to) biological, physical and psychosocial risks (which may impact mental health and well-being). The COVID-19 pandemic has introduced new occupational risks, which vary substantially between occupations.
This rapid response outlines types of occupational risks related to COVID-19, and how they vary by occupation and over the time-course of the pandemic response. It also considers protective factors and actions that governments and employers are taking to keep workers safe.
The Office for National Statistics reported that there were 5,330 deaths involving COVID-19 in the working age population (aged 20 to 64 years) between 9 March and 30 June.
Occupations with elevated COVID-19 related death rates included health and social care workers, security guards, bus/coach/taxi drivers, construction workers, cleaners, and sales and retail assistants.
The Office for National Statistics estimates that 72% of these deaths were as a result of contracting SARS-CoV-2 before the national lockdown began on 26 March. During lockdown, many workers may not have attended work (due to remote working, business closures or furlough schemes), and those that did attend work are likely to have had reduced contact with others.
Many occupations, such as those in the healthcare sector, have experienced increased occupational risks as staff duties involve close proximity with people infected with the virus. Other industries appear to be more prone to workplace outbreaks amongst employees (such as in food processing plants) because of specific working conditions.
Health and social care professionals encounter the highest occupational risks, as they provide essential care for people who are symptomatic or confirmed to have COVID-19. This means that they have prolonged close contact with the virus.
According to a survey of 120,000 UK residents, healthcare professionals were over seven times more likely to test positive for COVID-19 compared with non-essential workers. Social care workers were over three times more likely.
Between April and the June 2020, a voluntary testing programme of 9,909 staff at a UK teaching hospital found that 11% tested positive for COVID-19 at some point. The highest rates were found in COVID-19 frontline areas (21%).
In addition to physical health risks, the Institute for Public Policy Research found that 50% of 996 UK healthcare workers reported that their mental health had deteriorated since the pandemic began. Healthcare workers were under strain due to greater personal risks, as well as being more likely to know somebody who had been hospitalised or died during the pandemic. In April, the NHS launched a mental health hotline to provide psychological support for staff tackling COVID-19.
According to the European Centre for Disease Prevention and Control, there were 1,376 clusters of COVID-19 outbreaks in occupational settings across Europe between March and early July 2020. If not prevented or quickly controlled, workplace outbreaks may contribute to a local resurgence of COVID-19 cases. Identifying which workplaces are vulnerable can help prevent and reduce the rate of virus spread, as academic research indicates that up to 80% of transmission is potentially caused by only 10% of infected individuals.
The Wellcome Open Research COVID-19 working group identified COVID-19 outbreaks occurring in food processing plants in multiple countries, sometimes producing over 500 cases from a single workplace. The greater spread of the virus in these environments may be due to the cold atmosphere, close proximity of workers for prolonged periods, or the increased projection of viral particles when workers speak loudly over industrial noise.
It is also likely that factory outbreaks occurred more frequently in food production facilities because many other factories closed or were working at reduced capacity during lockdown, whereas food production continued as an essential service.
So far, workplace data related to COVID-19 are preliminary. SAGE has outlined a need for a systematic review of the settings where outbreaks have been reported to help understand what makes occupations high risk. SAGE also noted that it is beneficial to review settings where transmission rates are low despite high levels of potential risk, as this can be used to inform effective preventative measures.
Based on US data from 2019, the Office for National Statistics has estimated which occupational factors increase the risk of contracting COVID-19. These include:
The European Centre for Disease Prevention and Control identifies working indoors, meetings with multiple people in the same room and sharing work facilities (such as canteens, kitchens and toilets) as additional risk factors, particularly if people work in confined spaces.
Business closures and furlough schemes mean that many workers were not exposed to occupational risks during the initial peak of the pandemic but may now be exposed after returning to work. Over 9.6 million employments were furloughed for at least part of the period between March to June 2020.
Many industries were closed during lockdown, as they were identified as environments at high risk of COVID-19 transmission. These included businesses in the hospitality and beauty sectors. Many workers did not encounter occupational risk during this time because they were unable to work. However, these employees may now be at a higher risk of contracting COVID-19 due to the re-opening of public services and easing of restrictions.
Some populations have greater risk of being infected with SARS-CoV-2 due to their higher likelihood of being employed in at-risk occupations. These include people with low incomes and people from minority ethnic backgrounds.
Of the 16 occupations defined as having the highest risk, six are paid below the median wage in England and Wales (£13.21 per hour). These include care escorts (who accompany vulnerable people on local journeys), dental nurses and nursing assistants.
In England, 74% of COVID-19 related deaths in male elementary workers (those working in routine tasks such as security, cleaning and construction) were in those who lived in deprived neighbourhoods. The death rate was three times higher than average for those that lived in the most deprived quartile.
One academic study suggests that low-skilled workers (such as those that work in transport operation, food production and retail) are at increased risk of exposure to colleagues who are asymptomatic or who continue to report for duty despite contracting the virus.
Financial insecurity may provide a deterrent for missing work in low-paid occupations. Low-skilled workers may also experience less access to testing, which means there is a less chance of COVID-19 being detected, particularly in asymptomatic individuals.
People from ethnic minority groups may experience greater occupational risks related to COVID-19, as they are over-represented in key worker roles. For example, the Institute for Fiscal Studies shows that working-age Black British people are 50% more likely to be key workers than working-age White British people.
The Institute for Fiscal Studies highlights that the impacts have not been uniform across ethnicities, and aggregating all minorities together misses important differences. Where possible, the specific effects on different communities are discussed separately.
The Runnymede Trust estimated that 41% workers of Black African origin worked outside of their home during lockdown, compared with 27% of White workers. Workers from Chinese, Indian, Pakistani, Bangladeshi, Black African and Black Caribbean backgrounds were twice as likely to use public transport to travel to work.
The healthcare sector has come under particular scrutiny. In April, the Health Service Journal found that Black and Asian NHS staff were over-represented in COVID-related deaths compared with their ethnic representation within the workforce. In comparison, White NHS workers were under-represented.
The NHS Confederation BME Leadership Network reported that Black and Minority Ethnicity NHS staff are less likely to speak up when they have concerns about personal protective equipment (PPE).
The British Medical Association found that only 29% of Black, Asian and Minority Ethnic doctors felt sufficiently protected from COVID-19 compared with 46% of White doctors. An earlier survey conducted in April indicated an even starker contrast (33% compared with 64%).
The UK-REACH study, a partnership of researchers and clinicians, has been approved to further investigate how ethnicity affects COVID-19 clinical outcomes in healthcare workers.
People from ethnic minority groups may be at higher risk of workplace outbreaks. A US study found that Hispanic and Black, Asian and Minority Ethnicity workers accounted for 73% of workplace outbreak cases in Utah between March and June, despite representing only 24% of workers in the affected sectors. Manufacturing, construction and wholesale trade workers were among those most affected.
The European Centre for Disease Prevention and Control recommends that workplaces have robust policies on social distancing, hygiene/cleaning, personal protective equipment (PPE) and contact tracing to prevent further outbreaks.
SAGE advocates that employers should run educational campaigns to support employees, by working with them, monitoring progress and collecting feedback on effectiveness and discrimination.
The public has been advised to work from home wherever possible. However, data from the European Union estimate that only 35% of jobs can be performed at home, which means that some occupations are potentially more exposed to COVID-19 compared with others.
A survey of 120,600 UK workers showed that 29% of respondents were essential workers who continued to work outside of the home throughout the pandemic. According to a survey of 35,000 people in England, the risk of testing positive for COVID-19 was 2.5 times higher in people who worked outside of the home during lockdown.
The Office for National Statistics reported that workers in higher management have had significantly lower rates of COVID-19 related deaths compared with the general population, particularly during lockdown. This may be attributed to reduced contact with the public and being able to work from home.
SAGE has advised that working one week with contact and one week without contact (for example, through remote working) would minimise the risk of transmission. This is because transmission would be limited to employees on the same schedule and people with asymptomatic infections should become non-infectious by the end of the non-contact week.
The European Centre for Disease Prevention and Control has stated that maintaining physical distance is the most important contributor to preventing occupational outbreaks, particularly when people are sharing the same confined space for extended periods of time.
Physical distancing is particularly important for protecting against aerosol transmission. Most personal protective equipment, including standard surgical face masks, do not provide much protection against aerosol transmission. This route of transmission is thought to be less frequent than contracting the virus through respiratory droplets or contact with contaminated surfaces, but it is more likely to occur in crowded or indoor spaces.
SAGE has advised that people with different networks should avoid meetings or prolonged social contact. For example, employees should avoid using different office floors. The report also notes that people providing supervision (such as managers) or support (such as IT) have the potential to spread the virus across different teams.
According to SAGE and the Health and Safety Executive, employers should ensure that employees have adequate access to handwashing facilities. Workplaces should be well-ventilated and cleaned frequently. The Health and Safety Executive advises that people should reduce their contact with different surfaces and employers should discourage movement around the workplace.
There have been instances of outbreaks where workers share transport or accommodation, which can be over-crowded with poor hygiene conditions. The European Centre for Disease Prevention and Control has highlighted this as a particular concern for seasonal or migrant workers, who may have travelled from areas with a higher incidence of COVID-19, and who work in jobs with reduced access to handwashing facilities (such as farm work).
Personal protective equipment (PPE) refers to equipment that protects users against health or safety risks at work. Many workplaces have introduced new PPE protocols in order to protect workers from COVID-19.
An academic study of over 810,000 people has shown that PPE can reduce the risk of contracting COVID-19, provided that it is widely available and of sufficient quality. However, re-using PPE will substantially reduce its protection due to self-contamination or the breakdown of materials. This indicates the need for clear protocols on access to PPE and disinfection prior to re-use.
The Health and Safety Executive has published guidance on the use of PPE for employees in non-healthcare settings. Since evidence is limited, the UK Government advises that good hand hygiene and social distancing is key to minimising the risk of infection.
SAGE recommends wearing a face covering if 2 metre social distancing is not possible, which is now required in many workplaces. Face coverings can help to prevent the transmission of COVID-19 by reducing the spread of respiratory droplets. You can read our rapid response on COVID-19 and face coverings here.
Widespread workplace testing is required to track and predict the spread of COVID-19. A lack of adequate testing may lead to infections being missed and higher rates of transmission, which is particularly problematic for asymptomatic cases. Under-reporting reduces the ability to understand the contribution of different workplace settings, which is essential for mitigating measures.
The European Centre for Disease Prevention and Control notes that testing in isolation is not enough to prevent workplace outbreaks. One academic study found that testing was only likely to be effective in high-risk work environments if tests were administered daily. Weekly testing was concluded to have limited value unless it was administered alongside other interventions (such as social distancing).
Inconsistencies in testing can make it difficult to estimate the comparative risks of COVID-19 in some workplaces compared with others. For example, the proportion of cases identified in the healthcare sector compared with other forms of essential work may be inflated as testing was prioritised in these settings. The European Centre for Disease Prevention and Control has commented that some European countries did not consistently report whether cases detected related to healthcare professionals or residents in social-care institutions.
Scientific Advisory Group for Emergencies (SAGE): Managing COVID-19 infection risks in high contact occupations
World Health Organization: Online course: occupational risks to health and safety during the pandemic
Association of Local Authority Medical Advisors: COVID-19 occupational risk calculator
European Agency for Safety and Health at Work: Adapting workplaces and protecting workers from COVID-19
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