Occupational risk for COVID-19

By Dr. Liji Thomas, MDMay 25 2020

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is continuing to take a heavy toll on human life, spreading to new regions even as its fire appears to have dwindled somewhat in the earlier epicenters of China and Europe.

Now, a new study published on the preprint server medRxiv* in May 2020 examines the risk of COVID-19 disease in various occupations, showing that as expected, health workers and those in social care occupation are at the highest risk. This should help guide policies to protect and support these occupations during this trying period.

Occupation and COVID-19

It is already known that essential workers are likely to be more exposed to the SARS-CoV-2 virus compared to other workers. Healthcare workers have been considered the highest risk category. The current study focuses on identifying other essential high-risk categories for whom similar protection may not be in place yet.

However, not much research has been done in the classification of risk in these groups. It is clear that all groups of the population are not at equal risk of infection. Especially vulnerable are essential workers (EW).

Occupation and risk of COVID-19: prospective cohort study of 120,621 UK Biobank participants. Image Credit: faboi / Shutterstock

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Occupational Risk of COVID-19 Among Essential Workers

Essential workers (EW) have come to the fore throughout this pandemic. These include frontline health workers, social workers, sanitation staff, and transportation staff. These groups of people have manned their posts throughout the pandemic, thus incurring a high level of exposure to the virus through their numerous contacts with the public.

Many workers in occupations traditionally relegated to the low-skill category, in addition to those operating transport, social services, food production and distribution, sales, and retail workers, are suffering higher rates of infection, illness, and death.

This type of prolonged exposure is all the more dangerous in that the majority may be with infected but asymptomatic individuals, or with colleagues who are sick or infected with the virus but continue to report for duty (a phenomenon called ‘presenteeism’).

Reasons for Increased Occupational Risk Among EW

Early research has shown that occupational exposure to the current virus is a matter of import to EW, and healthcare workers in particular, because of the lack of personal protective equipment (PPE). This has caused “a real and justified fear about personal safety.”

Which EW are at Highest Risk?

There is a lack of evidence as to which occupational groups are at the highest risk for COVID-19, other than healthcare workers who are generally recognized to be at the most risk. This has interfered with the framing of policies to support and prevent infections in other high-risk groups.

How Was the Study Done?

The current study aims to examine the risk of COVID-19 in EW vs. non-EW, using data from the UK Biobank Study and test results for the virus from PHE.

The aims include finding the risk of infection by:

• Broad essential occupational groups
• Detailed essential occupational groups
• Standard Occupational Classification (SOC) 2000 groups

The study will also account for confounding factors related to demographic and social characteristics, socioeconomic, job-related, lifestyle, and health factors. It is designed to be a prospective cohort study.

Participants were between 49-64 years in 2020, living within 25 miles of an assessment center, and registered with the National Health Service (NHS) of England. There were about 120,600 participants who were working at the time of baseline assessment, were below the age of 65 in March 2020.

All participants had undergone a baseline assessment at a center, with a physical and biological examination/test carried out, between 2006 to 2010. They had tested positive for SARS-CoV-2 in a hospital setting either as inpatients or at an Emergency Department. All others, whether testing positive or negative, outside such a setting, were outside the study group.

Classifying Occupations

The jobs were classified as non-EW, healthcare workers, social and education workers, police and protective services, and ‘others’). Within these categories, EW was classified into nine more precise categories such as medical support staff, health associate professionals, healthcare professionals, social care workers, education workers, food workers, transport workers, and police and protective services, including sanitation staff.

Of the over 120,600 participants, about 29% were EW, while healthcare workers made up 9%, and social and education workers 11%. About 86% had non-manual jobs, with just over half working less than 40 hours a week. About 91% of the participants were white.

EW comprised more females than males, at 38% vs. 21% respectively, and more blacks than whites (43% vs. 29% respectively).

Among this group, 817 participants had undergone hospital-based testing for COVID-19 between March 16 to May 3, 2020, which makes up less than 0.7% of the total number.

The Risk of Testing Positive Among EW

Among the total number of tested EW, 206 were positive (0.2%). The occupation-wise split-up was as follows:

• Healthcare workers - doctors, pharmacists (0.7%)
• Medical support staff - nursing assistants, hospital porters (0.8%)
• Health associate professionals - nurses, paramedics (0.7%)
• Social care (0.3%)
• Transport (0.2%)
• Police and protective service (0.2%)
• Non-EW (0.1%)

The study shows a higher risk of COVID-19 among EW. Healthcare workers had a 7.6-fold higher risk of testing positive compared to non-EW. This remained valid after adjusting for all potential confounding factors. Social and education workers had a more than two-fold risk after adjusting for other variables.

The Risk of Testing Positive Among Detailed EW Groups

Compared to non-EW, healthcare professionals were at a more than 6-fold risk, which became only higher at almost 9-fold when adjusted for other variables. Health associate professionals were at a still higher baseline risk of almost 8-fold, which became still higher after adjustment. Similarly, medical support staff had an almost 9-fold risk of testing positive compared to non-EW, which was reduced slightly to over 6-fold after adjustment.

For social care occupations, there was a 3-fold risk, which went down somewhat with adjustment. The risk for other EW was slightly higher than for non-EW, at almost 2-fold, but this was not significant.

The Risk of Testing Positive Among SOC 2000

By SOC 2000-based analysis, there was a threefold risk among associate professionals and technical workers compared to managerial and senior-level officials. This was not significantly reduced by adjustment for confounding factors.

The increased risk observed with personal service occupations and with employment in process, plants, and machine operations was found to drop significantly when adjusted by other confounding factors.

What Does the Study Mean for COVID-19 Risk for EW?

This study is the largest one yet to look at the risk of COVID-19 among various occupational groups. The more than 7-fold and 3-fold increase among healthcare and social care workers, respectively, seems to be unaffected by adjusting for other variables. This indicates the risk is linked to the occupation itself.

The large sample size and detailed data collection allowed the investigators to rapidly collect evidence that the ongoing pandemic was affecting specific occupations differently and to connect such outcomes to a broad range of factors such as work and lifestyle factors, and other medical conditions.

Limitations

The limitations are also obvious: baseline data were collected 10-14 years before the study began, which limits the present applicability of health and employment variables. The overwhelmingly white participation prevents its generalization to ethnic minorities and poorer groups.

Contradictory Results

It is worth noting that the results of the UK Office for National Statistics show the highest mortality rates from COVID-19 to occur among those working as transport staff, chefs, sales and retail assistants – but not among healthcare workers, compared to the general population. This difference may be due to the fact that while the infection is related to exposure, death rates are related to other health and sociodemographic factors.

For instance, as early Wuhan studies show, males and people with other medical conditions are more likely to die from the virus. Low-skilled workers are more likely to be poorer, to have restricted access to testing, and, therefore later diagnosis with a lower chance of receiving timely care.

What Can be Done to Protect EW?

In light of these findings, appropriate policies must be put in place in the workplace to prevent unnecessarily high rates of workplace exposure and the spread of infection. However, say the researchers, “Combining our findings with those of the ONS, it is clear that maintaining testing for essential workers is important; however, there is an urgent need for testing and protective measures to be extended to wider and more disadvantaged occupational groups.”

Further studies will be needed to evaluate how low-skilled younger workers respond to the infection, as well as the ethnic and occupational differences in the exposure, infection, and death rates. Proper interventions must be made in healthcare and social sectors to protect the vulnerable, since, as the researchers point out, “The wellbeing of essential workers is critical to limiting the spread, and managing the burden of global pandemics.”

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources