Temporal assessment of disparities in California COVID-19 mortality by industry: a population-based retrospective cohort study.

ABSTRACT

PURPOSE: To assess changes in the COVID-19 mortality rate and disparities over variants or waves by industry. METHODS: We identified COVID-19 deaths that occurred between January 2020 and May 2022 among California workers aged 18-64 years using death certificates, and estimated Californians at risk using the Current Population Survey. The waves in deaths were wave 1 March-June 2020, wave 2 July-November 2020, wave 3/Epsilon and Alpha variants December 2020-May 2021, wave 4/Delta variant June 2021-January 2022, and wave 5/Omicron variant February-May 2022. We used Poisson regression to generate wave-specific mortality rate ratios (MRR) and included an interaction term between industry and wave in different models to assess significance of the change in MRR. RESULTS: In all waves of the pandemic, healthcare, other services, manufacturing, transportation, and retail trade industries had higher mortality rates than the professional, scientific, and technical industry. The healthcare industry had the highest relative rate earlier in the pandemic, while other services, utilities, and accommodation and food services industries had substantial increases in MRR in later waves. CONCLUSIONS: Industries that consistently had disproportionate COVID-19 mortality may have benefitted from protections that consider workers' increased exposure and vulnerability to severe outcomes.