The Social Vulnerability Index and Covid-19 positivity among health care personnel, January 2021-May 2022: a case-control study within a multi-center study

Robert Paul Niezgoda

doi:10.25820/etd.008234

Background: COVID-19 health disparities have been associated with social determinants of health (SDoH), such as socioeconomic status, educational attainment, and demographic characteristics of age, race, and ethnicity. The Centers for Disease Control and Prevention Social Vulnerability Index (SVI) measure of community-level SDoH has also been associated with health disparities. Understanding the influence of social vulnerability on HCP is important to identify workers within the healthcare system who are most at risk of morbidity and mortality during public health emergencies so that strategies can be implemented to protect these workers to maintain the healthcare system infrastructure. Previous research has not explored the association of community-level SDOH conditions where healthcare personnel (HCP) from various occupational groups who differ by race, ethnicity, socioeconomic status, and educational attainment live using the SVI as a population-level risk factor while exploring individual HCP characteristics and self-reported community exposures during the COVID-19 pandemic. Additionally, researchers have studied personal protective equipment (PPE) adherence, design, and processes of use and training received by HCP in the work setting. However, the association of HCP self-efficacy of using recommended PPE and training received with COVID-19 positivity has not been explored. All these factors are important considerations for protecting HCP so that the healthcare system infrastructure in maintained during pandemics and other emergencies. If social vulnerability among HCP is identified as an important preparedness consideration, additional strategies can be implemented to protect vulnerable HCP who are essential to healthcare system operations. The objective of Aim 1 was to examine the association between community-level SVI exposure and COVID-19 positivity among HCP in academic medical centers. Aim 2 explored associations of self-reported community exposures and COVID-19 positivity among HCP outside of the work setting, while Aim 3 examined PPE comfort with using recommended PPE and types of PPE training among HCP and COVID-19 positivity. Adjusted models considered HCP role, social vulnerability, and demographic characteristics. Methods: I completed a case-control study nested within the PReventing Emerging infections through Vaccine EffectiveNess Testing (PREVENT) study, a multi-center SARS-CoV-2 vaccine effectiveness study in 15 U.S. academic medical centers. Participants included HCP tested for SARS-CoV-2 between January 2021 and May 2022. Cases were identified if they tested positive for COVID-19 and reported COVID-19-like symptoms. Controls tested negative for COVID-19, with or without symptoms. Asymptomatic HCP who tested positive for COVID-19 were excluded from the PREVENT study. Multivariable regression models were developed for each Aim. Aim 1 included an aggregate measure for residential ZIP code SVI exposure and outcome of COVID-19 positivity. Aim 2 measures included self-reported community exposures such as close-contact with someone in the community with confirmed COVID-19, attended a public mass gathering, use of public transportation (carpool, vanpool, taxi, or ride sharing service), use of shared transportation, shopped for items in a store, attended social gatherings, and use of face masks while in public. Social vulnerability was determined using the Centers for Disease Control and Prevention’s Social Vulnerability Index (SVI). I examined self-efficacy of PPE use and PPE training received in Aim 3 with measures for HCP role, demographic characteristics, community social vulnerability, average hours worked, educational attainment, urban/rural designation, COVID-19 vaccination, and SARS-CoV-2 variant timeframe in the adjusted model. Results: There were 6,957 HCP (3,124 COVID-19-positive cases [44.9%], 3,833 COVID-19-negative controls [55.1%]) in Aim 1. The three-level categorical variable of Aggregate SVI was not associated with COVID-19 positivity when adjusting for race, ethnicity, age, biological sex, educational attainment, rurality, and COVID-19 variant timeframe (High aggregate SVI aOR: 1.12, 95%CI: 0.96, 1.31. High household composition and disability SVI theme was associated with COVID-19 positivity (aOR 1.21, 95% CI:1.04, 1.41). In Aim 2, I observed greater odds of COVID-19 positivity among HCP with self-reported contact with someone in the community with confirmed COVID-19 (aOR: 3.55, 95% CI: 3.06, 4.13); and face mask use [sometimes aOR: 1.51, 95% CI: 1.30, 1.75), rarely (aOR: 2.10, 95% CI: 1.59, 2.76), or never (aOR: 1.58, 95% CI: 1.01, 2.48)]. Lower odds of COVID-19 positivity were observed for going shopping for items in stores (aOR: 0.66, 95% CI: 0.52, 0.83); going to hair salon or barber (aOR: 0.72, 95%CI: 0.63, 0.82); and visiting with less than 10 people not from household (aOR: 0.65, 95%CI: 0.57, 0.74). Bivariate analyses of community exposures identified decreased odds of COVID-19 positivity with increased self-reported face mask use in public. HCP with low self-efficacy of correctly using recommended PPE had greater odds of COVID-19 positivity (aOR=1.58, 95% CI: 1.02, 2.44). HCP receiving all training forms of PPE training (aOR=1.40, 95% CI: 1.11, 1.77) had greater odds of COVID-19 positivity as compared to those only receiving online training. Secondary analysis of PPE comfort and training by HCP roles (clinical, non-clinical, other) identified that discomfort with using recommended PPE correctly was associated with greater odds of COVID-19 positivity among HCP with non-clinical roles (aOR=1.81, 95% CI: 1.04, 3.16) but not for HCP with clinical roles. Limitations: My study has several limitations. First, I used ZIP code level SVI whereas previous studies used census tract level SVI metrics. This could have led to some misclassification bias in HCP SVI level due to the transformation of census tract level SVI to a ZIP code level metric. Second, the SVI has been criticized for its weighting methods that contribute to poor precision.1,2 My approach minimized misclassification bias of SVI by comparing SVI of ZIP code of HCP residence pre- and post-transformation of census tract level SVI to ZIP code level. This allowed me to identify instances where ZIP code level SVI population-weighted averages differed from census tract SVI scores. Through my conversion process, I observed very low levels of misclassification of 0.12% to 1.95% across SVI themes and levels (high, medium, low) which were unlikely to meaningfully change observed associations. Third, my sample is under-represented in Black or African-American participants (7.8% versus 12.1% of U.S. Healthcare workforce). A more representative sample may have contributed to a change in borderline associations between low- and high-SVI themes as was the case of the socioeconomic status SVI theme. Whereas the associations observed with other SVI themes (minority status; and housing and transportation) would have likely changed very little. Another limitation involves the questionnaire of the PREVENT study which was not specifically designed to explore self-reported community exposures and PPE self-efficacy in greater detail. The definitions of the self-reported community exposures resulted in a crude determination of community exposure status. Important factors that would contribute to disease transmission such as duration of exposure, frequency of exposure, crowding, and presence of other disease transmission precautions were not included in the questionnaire for self-reported community exposures. It is likely that misclassification of exposure status was present resulting in bias of the measures of effect. Limitations were also present that likely obscured associations of self-reported comfort with use of recommended PPE and COVID-19 positivity. Questions could have been specifically developed for the current study to clarify HCP levels of self-efficacy of properly using recommended PPE and COVID-19 positivity as the current questions were not structured to measure self-efficacy of use of recommended PPE. Additionally, question structure may have resulted in participants focusing on physical comfort rather than comfort with properly using recommended PPE. Information concerning physical comfort, proper use of PPE, previous trainings, work experience with PPE, or other circumstances that would impact SARS-CoV-2 transmission was not collected. The self-reported assignment of comfort with properly using recommended PPE was subjective without a standardization of levels of comfort of use. Efforts were made to consider each of the limitations present to include variables to account for confounding or to consider limitations in the analyses and interpretation. When considering the identified limitations, each may have resulted in either differential or non-differential misclassification bias. This would result in the observed measures of associations being either higher or lower than the true values if the bias were not present. Consequently, the significant associations present could have been weaker or stronger than what was observed. Conclusions: I found that high aggregate SVI was not associated with increased odds of COVID-19 positivity among included HCP when controlling for HCP role and demographic characteristics of race, ethnicity, sex, age, educational attainment, rurality, and SARS-CoV-2 variant time frame. This is distinct from prior work. However, my results measured the association of population-level SVI exposure within an individual-level analysis. I did observe that high social vulnerability in community household composition and disability status SVI theme (See Table 1-2 for SVI themes details) was associated with greater adjusted odds of COVID-19 positivity among HCP which was consistent with previous work of population-level studies using SVI of the general public. In Aim 2, I found, that some HCP self-reported community exposures resulted in lowered odds of COVID-19 positivity according to self-reported face mask use. This effect was thought to be due to other protective behaviors that were followed such as social distancing. Face mask use was considered a hallmark of those who followed other public health preventive behaviors leading to an overall protective effect. For Aim 3, HCP reports of being very uncomfortable with using recommended PPE were associated with greater odds of COVID-19 positivity. Training modality was not associated with decreased odds of COVID-19 positivity. Findings suggest that asking HCP about comfort with using recommended PPE as a measure of self-efficacy could be a strategy to identify HCP more likely to be at greater risk of COVID-19 positivity. Future work should clarify the utility of the SVI for public health preparedness efforts for HCPs. This includes increasing our understanding of associations that exist between different SVI themes, individual demographic characteristics, and health risks during other types of public health emergencies. Additionally, efforts should focus on clarifying face mask use in public and behaviors that may reduce community exposures during a pandemic. More research is warranted regarding the use of self-efficacy as an indicator of using recommended PPE correctly or for identifying HCP who may be at increased risk of disease transmission to improve pandemic response and infection control practices. My findings contribute to our understanding of the SVI as a community-level exposure when considering individual characteristics. These findings suggest that some community-level SVI measures and individual characteristics contributed to COVID-19 positivity; demonstrating complex combinations of factors. Community-level exposures were found to contribute to COVID-19 positivity while less face mask use was a factor that contributed to greater odds of COVID-19 positivity. This is important as it suggests that a combination of behaviors may have contributed to this finding. My findings also suggested that self-efficacy could be an important indicator of using recommended PPE correctly or for identifying HCP who may be at increased risk.

The Social Vulnerability Index and Covid-19 positivity among health care personnel, January 2021-May 2022: a case-control study within a multi-center study

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