AgdaPkt 2021.04.12 Joint SA PFA - Complete Agenda Packet

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� JY Netherlands investigated the viral genetic sequences of affected HCWs and found the infection was more likely to be acquired from the communities.24 In our current study, we did not observe a difference in SARS-CoV-2 community prevalence among those tested positive versus negative employees, indicating the possi- bility of a true work-related SARS-CoV-2 exposure. In terms of exposure risk, >90% of employees with positive assay result had a position with significant direct exposure to customers. We also found that employees in supervisory positions, with exposure from both customers and colleagues, had increased SARS-CoV-2 exposure risk. Employees in supervisory positions may have more exposure due to frequent interpersonal contacts, therefore leading to their higher infection rates. Notably, most of the SARS-CoV-2-positive assay workers were asymptomatic at time of testing. As evidence has shown probable transmission from asymptomatic or mildly symptomatic carriers,3 25 26 these workers as a cluster carries significant risk to their customers, colleagues and families. Our findings further strengthens the retail cluster transmission observed in a previous study from China, which involved supermarket employees, clients and the families of affected cases, resulting in a infection rate of 9.2% among the market workers. 17 In this cohort, cigarette smoking was found to be a protective factor of SARS-CoV-2 RT -PCR assay result in the crude analysis. Despite a lack of statistical significance after IPW adjustment, our finding echoes a recently published systematic review indicating lower smoking prevalence among patients with COVID-19 in comparison with the general population. 27 In that review, the authors pooled 13 Chinese studies on hospitalised patients with COVID-19 and found a prevalence of 6.5% of current smokers, which was around one-fourth of the smoking prevalence among the general population. The potential biological mechanism involving nicotinic receptors has been proposed in another study. 21 In fact, research has shown nicotinic receptor activity can promote SARS-CoV-2 transmission through co -expression of ACE2 receptor, the host receptor for the virus. Therefore, the competitive nature of nicotine and SARS-CoV-2, as a nico- tinic agent, for the receptor may serve as a key to prevent the infection. 28 Our finding of fewer current smokers with a positive SARS-CoV-2 assay result, while in agreement with recent epide- miological studies, contradicts common perception and clinical recommendation on risks and effects of cigarette smoking on lung health warranting further research investigations. 29 While previous research has raised concerns on psycho- logical distress due to COVID-19 in addition to physiological threats on essential workers,ll most of them were focused on HCWs. 10 15 30-32 The prevalence of anxiety among HCWs in other countries ranged from 20% to 65% during the COVID-19 pandemic. 11 30 32 In our study, 24% of these workers had at least mild anxiety, suggesting non -HCWs essential employees experience similar level of psychological distress. Contrary to common beliefs on the association between sufficient PPE and employees' psychological distress, 33 34 the inability to practice social distancing consistently at work was a significant risk factor for anxiety and depression in this essential worker cohort. While we are unable to discern the direction of the effect due to the cross-sectional nature of this study, these mental health findings support the need to implement further preventive strategies and to provide additional mental health assistance to essential employees. Our current study has several limitations. First, our limited sample size may prevent identification of certain associations that may require larger statistical power, and incidental find- ings may by chance be observed in a small sample -sized study. 242 However, the large effect sizes (ie, ORs) are unlikely to be entirely biassed by unmeasured confounding factors. Second, this is a cross-sectional study and therefore causal relationship could not be inferred. At the same time, survey collection was conducted prior to SARS-CoV-2 RT -PCR sampling, suggesting our major findings should be free of reverse causation and any recall bias would be minimised. Third, while a majority of the employees from this retail store were tested at this designated location, some employees received testing at other clinics due to insurance, scheduling and/or location convenience. As this was a city -mandated testing, employees were assigned by the retail headquarter to be tested at this location if they had not received or scheduled to receive SARS-CoV-2 testing. Selection was neither based on their exposure risk nor health outcome and therefore the current study should be free of selection bias. Lastly, since our data collection was largely based on self- reported questionnaire, we incur unavoidable risk of measure- ment error, misclassification and related information bias. At the same time, our study enjoys several strengths. First, the SARS-CoV-2 RT -PCR assay samples were collected by naso- pharyngeal approach which provides the highest test sensitivity among all methods 35 and the outcomes of interest were assessed by validated screening tools including GAD -7 and PHQ-9. The possibility of outcome misclassification was therefore mini- mised. Second, our secondary sensitivity analysis results were in accordance with the main analysis which further strengthened our findings. Third, our study participants were restricted to grocery retail employees from one store and such restriction could eliminate potential confounding factors such as socioeco- nomical status. Lastly, we included all workers that were sched- uled and presented to the testing tent during group testing days without any exclusion criteria. As a result of our strengths, find- ings in this study may be generalised to grocery store employees working during the COVID-19 pandemic in similar settings. In conclusion, in this cohort of grocery retail essential workers, 20% had a positive SARS-CoV-2 RT -PCR assay result and the majority (76%) of them were asymptomatic at time of testing. Employees with direct customer exposure were five times more likely to have a positive SARS-CoV-2 assay result. The ability to social distance consistently at work was a significant protec- tive factor for anxiety and depression. Commuting to work by public transportation/shared rides and having an exposure to a confirmed case within the past 14 days were positively asso- ciated with depression. Further research is warranted to inves- tigate these associations and their public health implications among essential employees. Contributors JY designed the study and collected the data. F -YL conducted data analysis and drafted the manuscript. F -YL, CS, SNK and JY all contributed to the interpretation of the data, revising the manuscript and final approval. JY supervised the project. Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors. Competing interests SNK has received COVID-19-related consulting fees from Open Health. Patient consent for publication Not required. Provenance and peer review Not commissioned; externally peer reviewed. Data availability statement De -identified data are available on reasonable request. Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability Lan F -Y, et al. Occup Environ Med 2021;78:237-243. doi: 10. 1 136/oemed-2020-106774 396 0