local Institutional Review Board . Based on available data at the time , sample size was determined with the assumption that positive antibody rates in healthcare workers would be 10 % and in community workers would be 20 %. With a power of 0.8 , the number of participants were determined to be at least 468 individuals . A total of 1,081 essential workers were voluntarily recruited by study flyers and word of mouth . The only exclusion criterion were individuals less than 18 years of age . Essential workers were defined as workers from local healthcare facilities , retail establishments , schools , and other essential businesses working outside of their homes . These workers were grouped by profession with HCW defined as individuals in the medical profession , including emergency medical services ( EMS ) personnel whose job responsibilities included direct patient care . Community essential workers were defined as first responders such as individuals in law enforcement and the fire department and various other professions such as restaurant workers , teachers , and grocery workers . After obtaining informed consent , questionnaires were completed by the participant describing COVID-19 symptom history , contact exposure , prior COVID-19 testing , and employment . Blood samples were obtained on the same visit and tested for SARS-CoV-2 IgG antibodies .
Gender
State of Residence
County of Residence
Profession
Home
TABLE 1 : Demographics of Participants |
Demographics |
N (%) |
Male |
463 ( 43.0 ) |
Female |
618 ( 57.0 ) |
West Virginia |
1,056 ( 97.7 ) |
Ohio or Kentucky |
10 ( 0.9 ) |
Other |
5 ( 0.5 ) |
Did Not Disclose |
10 ( 0.9 ) |
Kanawha |
649 ( 61.7 ) |
Putnam |
247 ( 23.6 ) |
Cabell |
65 ( 6.2 ) |
Jackson |
21 ( 1.9 ) |
Boone |
13 ( 1.2 ) |
Roane |
10 ( 0.9 ) |
Other |
32 ( 3.0 ) |
Did Not Disclose |
44 ( 4.1 ) |
Community Essential Worker |
618 ( 57.6 ) |
Healthcare Worker |
458 ( 42.4 ) |
Work with Covid Patients |
256 ( 23.7 ) |
Living Alone |
107 ( 9.9 ) |
Living with Children |
483 ( 44.7 ) |
Living with Adult |
634 ( 58.6 ) |
Covid Positive Household Contact |
75 ( 6.9 ) |
Covid Positive Person Contact |
641 ( 59.3 ) |
This research complied with all relevant national regulations and institutional policies and was approved by the Institutional Review Board of Charleston Area Medical Center ( CAMC ) Institute of Academic Medicine . Informed consent was obtained from study participants . This study was supported by a grant from the CAMC Institute and West Virginia Clinical & Translational Science Institute with the National Institute of General Medical Sciences of the National Institutes of Health .
SAS 9.4 was used to analyze the data for this study . Univariate analyses including t-tests were used for numerical variables while chi-square analysis was used for categorical variables . Multivariate regression analysis was applied to determine which variables were related to the COVID-19 test result . Questions that were not answered on the intake survey remained missing .
RESULTS
A total of 458 HCW and 623 CEW were enrolled ( N = 1,081 ). Table 1 provides participant demographics . Of the participants , 641 ( 59.3 %) had exposure to a positive patient with only 7 % reporting an exposure in their household .
Although 532 ( 49.2 %) participants had previously tested for COVID-19 , only 221 ( 20.5 %) of the participants believed that they had previously contracted COVID-19 with only 50 ( 4.6 %) reported previously testing positive with a PCR test ( Figure 1 ).
A total of 84 participants were found to have positive COVID-19 antibodies ( 81 reactive , 3 equivocal ) representing 7.8 % of all essential workers tested . None of the participants were vaccinated prior to testing due to lack of availability at that time . There were no statistically significant differences in risk of a positive antibody test , including gender ( 7.78 % male , 7.77 % female , p = 1 ), living alone or with others ( 5.52 % vs . 7.87 %, p = 0.91 ), living with or without children in your home ( 8.9 % children , 7.61 % none , p = 0.75 ) or based upon the month of the testing ( 8.47 % September-October vs . 7.32 % November-December , p = 0.6 ). There was no significant difference between healthcare workers working on COVID-19 units compared to those working on non- COVID units ( 11.3 % vs . 9.41 %, p = 0.54 ).
Multiple risk factors for a positive COVID-19 antibody test were identified in our study ( Figure 2 ), including having a known close exposure to a person with COVID-19 ( 11.3 % vs . 2.79 %, p < 0.001 ) and living in the same home as someone known to have COVID-19 ( 46.7 % vs . 4.9 % p < 0.001 ). Additionally , simply being previously tested , regardless of the result , increased the chances of
West Virginia Medical Journal • June 2023 • 17