Is Outsourced and Shift Work Associated with an Increased Risk of COVID-19? Findings from a Study about Mining Workers

Objectives: to investigate the sociodemographic and occupational risk factors associated with COVID-19 infection in mining workers. Methods: a retrospective cohort study, using secondary workers’ health data from a multinational mining company, from March 2020 to April 2021. A COVID-19 case was defined based on a SARS-CoV-2 positive result in a polymerase chain reaction (PCR) test. Risk ratios (RRs) for positive testing were estimated using Poisson’s regression model. Results: of 10,484 workers, 2,578 (24.6%) had at least one positive result for COVID-19. Each worker underwent an average of 4.0 (standard deviation: 3.6) tests, totaling 41,962 PCR tests. Most of the evaluated workers were male (88.3%), aged from 30 to 39 years (38.7%), outsourced (74.1%) and non-shift workers (70.5%). Our multivariate model showed that outsourced (RR: 1.39; 95% confidence interval [95%CI]: 1.27;1.51) and shift workers (RR: 1.10; 95%CI: 1.01;1.20) had a higher risk of SARS-CoV-2 infection than their counterparts. Conclusions: outsourced and shift workers have a higher risk of COVID-19 infection than their counterparts. Therefore, it is necessary to provide continuous monitoring with regular and adequate testing for mitigation and prevention of COVID-19 in these occupational groups.