More COVID-19 in some occupational groups
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There were more registered cases of COVID-19 in some occupations than in others, according to a new study from the Norwegian Institute of Public Health. Occupations with a potentially increased risk include drivers, healthcare personnel and employees in bars and restaurants.
Researchers at the Norwegian Institute of Public Health have investigated whether occupational groups with frequent contact with customers, students, users or patients have an increased risk of COVID-19. Data are retrieved from health registries and other registries.
“We see that healthcare personnel and drivers were most exposed in the first period of the epidemic in the winter and spring of 2020. This autumn, we did not find more cases of COVID-19 among healthcare personnel than among other groups. The risk may have been higher this autumn for employees that meet many customers, such as bartenders and waiters,” says Karin Magnusson, researcher at the Norwegian Institute of Public Health and first author of the study.
The most important findings
The results are preliminary and show that in the period from February to mid-July 2020 there were:
- 2.3 COVID-19 cases per 1 000 people in their working age (20-70 years) in Norway.
- Among health professionals such as physiotherapists, dentists, nurses and doctors, there were 3.5 to 6.5 cases per 1 000, which is 1.5 to 3 times more than in the rest of the population of working age.
- Among taxi drivers, bus drivers and tram drivers, there was a similar increase: from 3.4 to 5.5 cases per 1 000.
In the period from mid-July to mid-October 2020 there were:
- 2.6 COVID-19 cases per 1000 people of working age in Norway, which is higher than in the first period.
- Most vulnerable in the second period were employees in the catering industry, such as bartenders and waiters, as well as flight attendants and boat stewards. The number of COVID-19 cases ranged from 6.2 to 8.9 per 1 000.
- Among healthcare personnel, the number in the second period was lower or at the same level as among others of working age.
- Among bus drivers and tram drivers, there were similar levels as among other people of working age, however there were more cases among taxi drivers (4.2 per 1000).
Results per occupational group
The results are divided by occupational group. Among teachers, there were no more COVID-19 cases when compared to everyone in their working age, this applies to both periods.
The number of confirmed COVID-19 per 1000 working people in different occupations in Norway, before and after 18 July 2020. Vertical lines show the proportion of confirmed cases for everyone of working age (20-70 years) for the two periods.
Test criteria can explain differences between periods
“The difference between the first and second wave may be due to changes in the test criteria. In the first wave, there was a shortage of test equipment, and patients, risk groups and healthcare personnel were prioritised for testing. In the second wave, close contacts and people with mild symptoms could also be tested. Another explanation may be infection control measures, including the fact that fewer people went abroad on holiday,” says Magnusson.
“The high proportion of doctors who were infected in the first period may, for example, have been infected on holiday in Italy, and not in Norway at the doctor's office. However, we do not know this, so one explanation could therefore also be better protection of healthcare personnel. In future studies, we can put several possible explanatory factors together and learn more about the risk of infection in different settings,” she adds.
There were no differences between occupational groups for severe COVID-19 disease and admissions to hospital. Dentists were the exception, with more hospital admissions than other occupational groups. This raises the question of whether infection with a large dose of virus from individuals increases the risk of more serious disease, but the numbers are low and therefore uncertain.
About the study
The purpose was to study whether the risk of COVID-19 and admissions to hospital increased among workers in occupations with a lot of direct contact with other people, compared with others of working age.
The study includes more than 3.5 million inhabitants of working age, between 20 and 70 years. The average age was 44 years, and there was an equal distribution between men and women. Each occupational group was compared with the rest of the working population of working age, and the risk was adjusted for age, gender and country of birth.
Data about COVID-19 were retrieved from the Beredt-19 registry at the Norwegian Institute of Public Health. This registry combines data from, among others, the Norwegian Surveillance System for Communicable Diseases (MSIS), the Norwegian Patient Registry, the National Population Register and NAV's employer and employee register.
As far as the researchers are aware, this is the first national study on occupational activity and COVID-19 risk. The methods used are identical to those described in the reference (Magnusson et al., 2020), with updated data including November 3rd 2020.