Evaluating the association between in‐person work and the risk of SARS‐CoV‐2 infection through June 2021

Abstract

Objectives: Recent studies have evaluated COVID-19 outbreaks and excess mortality by occupation sectors. Studies on SARS-CoV-2 infection across occupation and occupation-related factors remain lacking. In this study, we estimate the effect of in-person work on SARS-CoV-2 infection risk and describe SARS-CoV-2 seroprevalence among working adults. Methods: We used Wave 1 data (May to June 2021) from CalScope, a populationbased seroprevalence study in California. Occupation data were coded using the National Institute for Occupational Safety and Health Industry and Occupation Computerized Coding System. Dried blood spot specimens were tested for antibodies to establish evidence of prior infection. We estimated the causal effect of in-person work on SARS-CoV-2 infection risk using the g-formula and describe SARS-CoV-2 seroprevalence across occupation-related factors.Results: Among 4335 working adults, 53% worked in person. In-person work was associated with increased risk of prior SARS-CoV-2 infection (risk difference: 0.03; [95% CI: 0.02−0.04]) compared with working remotely. Workers that reported job loss or who were without medical insurance had higher evidence of prior infection.Amongst in-person workers, evidence of prior infection was highest within farming, fishing, and forestry (55%; [95% CI: 26%−81%]); installation, maintenance, and repair (23%; [12%−39%]); building and grounds cleaning and maintenance (23%; [13% −36%]); food preparation and serving related (22% [13%−35%]); and healthcare support (22%; [13%−34%]) occupations. Workers who identified as Latino, reported a household income of <$25K, or who were without a bachelor's degree also had higher evidence of prior infection.Conclusions: SARS-CoV-2 infection risk varies by occupation. Future vaccination strategies may consider prioritizing in-person workers.

SARS-CoV-2 antibody prevalence by industry, workplace characteristics, and workplace infection prevention and control measures, North Carolina, 2021 to 2022

“…Many worksites with more than 1000 employees in this study were large pork processing facilities, with many other factors contributing to SARS-CoV-2 transmission risk—close proximity, long shifts, cold temperatures, low humidity, poor ventilation, and high levels of noise necessitating yelling to communicate (Taylor et al 2020; Waltenburg et al 2020; Klein et al 2022). Essential workers in our study also had somewhat higher adjusted odds of SARS-CoV-2 infection, consistent with other studies showing that workers exempted from earlier lockdowns and generally unable to work from home were more likely to be exposed to infected coworkers, customers, and patients (Carlsten et al 2021; Mutambudzi et al 2021; Meza et al 2023).…”

“…This is consistent with reports of high numbers of COVID-19 outbreaks, cases, and deaths among animal processing workers (Hawkins et al 2021; House Staff Memorandum 2021; Billock et al 2022; Cummings et al 2022; Luckhaupt et al 2023). Most studies of SARS-CoV-2 seroprevalence focus on healthcare workers, although some have found high seroprevalence among other essential workers, including farming workers (Boucher et al 2023; Meza et al 2023). Higher odds of SARS-CoV-2 infection among animal processing workers even in comparison to other largely high-risk worker groups (e.g., health care workers) underline the extremely high prevalence of COVID-19 infection we observed in this worker group.…”

“…Attenuation after adjusting for other covariates also suggests that generally later enrollment dates and more household occupants account for some of the higher SARS-CoV-2 prevalence among animal processing workers. Research on outbreaks, severe outcomes, deaths, and seroprevalence have all found higher risks of COVID-19 among health care workers compared to the general population (Mutambudzi et al 2021;Billock et al 2022;Luckhaupt et al 2023;Meza et al 2023). However, a previous analysis of data from most participants in this study did find higher prevalence of SARS-CoV-2 infectioninduced IgG among all industrial livestock operation workers and their household members compared to a healthcare worker cohort (prevalence ratio 2.5, 95% CI 1.8 to 3.3) (Gigot et al 2023).The lower odds of SARS-CoV-2 we observed among health care and social assistance workers might be due to the high proportion of study participants working in other high-COVID-19-risk jobs (e.g., animal processing).…”

“…Meza et al . used serology and infection and vaccination history to identify higher SARS-CoV-2 infection risk for in-person workers and certain occupational groups, including farming, fishing, and forestry, in California during summer 2021; however, their sample did not allow for quantification of infection risk among meatpacking or livestock workers (Meza et al 2023).…”

“…SARS-CoV-2 seroprevalence surveys have identified higher risk occupational groups, including meatpacking and farm workers, prior to widespread COVID-19 vaccine availability, but most focused on healthcare-related occupations (Klein et al 2022;Boucher et al 2023). Meza et al used serology and infection and vaccination history to identify higher SARS-CoV-2 infection risk for in-person workers and certain occupational groups, including farming, fishing, and forestry, in California during summer 2021; however, their sample did not allow for quantification of infection risk among meatpacking or livestock workers (Meza et al 2023).…”