Objective Occupational differences in COVID-19 are well documented, but the empirical evidence on potential reasons for these differences remains limited. Possible reasons include pre-existing health conditions. This study investigated occupational differences in COVID-19 disease severity and whether they can be attributed to pre-existing health conditions.

Methods Our study used German health insurance data covering 3.17 million insured individuals (age 18–67 years), with details on COVID-19-related hospitalization and mortality in 2020 and 2021, information on occupation (regrouped into four classifications) and pre-existing health conditions (divided into seven disease groups). In addition to descriptive statistics, we estimated multivariable Cox regression models with varying sets of adjustments.

Results We found clear occupational differences in COVID-19 hospitalization and mortality, with the highest risks for the production sector (especially manufacturing), commercial services (especially cleaning) and for low-skilled occupations. These findings persisted after adjusting for age, sex, and region, and also after mutual adjustment for other occupational classifications. We also found some evidence that the association between occupation and disease severity was partly explained by pre-existing conditions, especially in the case of low skill levels.

Conclusions Our findings provide support for occupational differences in COVID-19, where the occupational classifications under study were independently related to risk differences (eg, skill-level and job sector). Furthermore, we provide empirical evidence that differences by occupational skill levels are partly due to pre-existing conditions. This finding suggests that occupational inequalities in health increased during the pandemic, with those with poorer health who worked in disadvantaged occupations also being more likely to experience severe COVID-19 outcomes.

Key terms COVID-19; disease severity; Germany; medical condition; occupational difference; pre-existing condition; susceptibility; vulnerable worker

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