Overall tested cohort characteristics: Of the 72,909 individuals tested for COVID-19 in the CCHS Research Registry, there were 6,145 HCW and 66,764 non-HCW with over 90% of HCW and 75% of non-HCW tested from Ohio. There were 9% of HCW who tested positive for COVID-19 compared to 6.5% of non-HCW, p<0.001 (Table 1). The HCW tested were younger than non-HCW (median age 39.7 vs. 57.5, p<0.001) with more females (proportion of males 21.5 vs. 44.9%, p<0.001), higher proportion of Asian and lower proportion of Black persons (3.4 vs. 1.0% and 16.2 vs. 18.3%, respectively, p<0.001), higher proportion identifying as non-Hispanic (90.8 vs. 87.6%, p <0.001), higher median income, and higher proportion of non-smokers. The neighborhood characteristics of population density as measured per square kilometer was similar for tested HCW vs. non- HCW while the population per housing unit was slightly higher. The HCW were more likely to report an exposure to COVID-19 (72.0% vs. 17.0%, p<0.001) and also to report having a family member with COVID-19 (28.3 vs. 14.2%, p 0.005). Regarding presenting symptoms, a slightly higher proportion of HCW reported cough (32.0 vs. 29.6%, p 0.001), a lower proportion reported fever (15.0 vs. 19.5%, p <0.001) or shortness of breath (14.6 vs. 25.7%, p<0.001), while a higher proportion reported diarrhea (11.9 vs. 9.5%, p<0.001) and lower proportion reported vomiting (7.4 vs. 9.7%, p <0.001). Of note, the tested HCW were, in general, healthier than the non-HCW group. The HCW had a lower proportion of several comorbidities including chronic obstructive pulmonary disease(COPD)/emphysema, diabetes, hypertension, coronary artery disease, heart failure, cancer, history of transplant, or immunosuppressive disease and were more likely to have received the influenza vaccine (85.9 vs. 45.4%, p <0.001). The HCW tested had a lower proportion of previous prescriptions for immunosuppressive treatment, NSAIDs, steroids, carvedilol, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, or melatonin.
COVID-19 cohort characteristics and outcomes: There were 551 HCW and 4,353 non-HCW who tested positive for COVID-19 (Appendix Table 2). Of those who tested positive for COVID-19, a lower proportion of HCW were hospitalized compared to non-HCW (38 or 6.9% HCW vs. 1205 or 27.7% non-HCW) or were admitted to the intensive care unit (10 or 1.8% HCW vs. 470 or 10.8% non-HCW). In the group who tested positive for COVID-19, there was a greater proportion of HCW of Asian and White race compared to non-HCW (2.9 vs. 0.8% and 61.0 vs 56.4%, respectively), a similar proportion of HCW with a positive COVID-19 test had presenting symptoms of cough, fatigue, diarrhea, loss of appetite, and vomiting and a lower proportion had fever or shortness of breath. Lower proportions of HCW testing positive had COPD/emphysema, diabetes, coronary artery disease, heart failure, cancer, or immunosuppressive disease and were previously prescribed carvedilol, angiotensin converting enzyme inhibitors, angiotensin receptor blockers or melatonin compared to non-HCW. The neighborhood population characteristics of population density or population per housing unit did not differ for those HCW who tested positive and median income was slightly higher compared to non-HCW.
Overlap propensity weighting: Using the variables in the prediction model for COVID-19 test positivity,23 overlap propensity score weighting (Table 2) resulted in propensity score weighted proportions of 7.7 vs. 8.9 for non-HCW vs. HCW having a positive test and produced an overlap propensity score weighted odds ratio of 1.17 with a 95% confidence interval (CI) of 0.99-1.38 for a HCW having a positive test compared to a non-HCW (Figure 1a). Then using the variables which predicted hospitalization for COVID-19 infection, overlap propensity score weighting was applied (Table 3) with weighted proportions for being hospitalized 15.9 vs. 7.4 for non-HCW vs. HCW, an odds ratio of 0.42 (CI 0.26 -0.66) for a HCW being hospitalized for COVID-19 compared to a non-HCW. For ICU admission, weighted proportions were 4.5 vs. 2.2 for non-HCW vs. HCW with an odds ratio of 0.48 (CI 0.20-1.04) for HCW being admitted to the ICU compared to non-HCW (Figure 1a).
Subgroup analysis
We then compared characteristics of HCW identified as having positions that required direct contact with patients (“patient facing”) and those that did not. There were 5,159 HCW with patient-facing positions and 986 HCW in non-patient facing roles (Appendix Table 3). The HCW with patient-facing roles were younger (median age 38 vs. 47 years, p<0.001), with more females (proportion males 20.6 vs. 26.2%, p < 0.001), lower proportion of Black race and higher Asian race, and with greater proportion reporting exposure to COVID-19 (73.7 vs. 62.9%, p < 0.001). The patient-facing HCW had lower proportions presenting with fatigue or shortness of breath and higher proportion with loss of appetite. There were no significant differences in laboratory values upon presentation. The patient-facing HCW had lower proportions of some previously prescribed medications including NSAIDs, steroids, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and melatonin. The patient-facing HCW group had lower proportions of comorbidities including COPD/emphysema, diabetes, hypertension, coronary artery disease, cancer, connective tissue disease, and immunosuppressive disease. Applying the overlap propensity score weighting (Appendix Tables 4, 5; Figure 1b) showed patient-facing HCW with increased odds of having a positive SARS-CoV-2 test result (OR 1.60, CI 1.08-2.39, weighted proportions 8.6 vs. 5.5), and lower but non-significant odds of hospital admission (OR 0.88, CI 0.20-3.66, proportions 10.2 vs. 11.4) and ICU admission (OR 0.34, CI 0.01-3.97, proportions 1.8 vs. 5.2).
Temporal relationship between disease prevention measures and positive tests
The summary of the trend of SARS-CoV-2 positive test results in the study period is shown in Figure 2. The overall proportion of positive COVID-19 test results decreased during the study period and the trend for HCW and followed that of non-HCW.