FIGURE 3 : COVID-19 Antibody Results with Prior Participant Characteristics COVID-19 Suspected by Participant
A
25.8 % 74.2 % 84.0 % 16.0 %
Positive Antibody
This study confirmed that essential workers who were required to work outside of their homes during the pandemic had nearly 60 % increased risk of COVID-19 compared to the public at the same time in WV ( 7.8 % vs . 4.9 %). Our hypothesis that HCW had a higher risk than other CEW proved true with antibody rates of HCW more than two times that of the cumulative positive COVID-19 incidence in the state at the time ( 10.5 % vs . 4.9 %) and nearly two times that of CEW ( 10.5 % vs . 5.8 %). The rate of positive antibodies in CEW was similar to the state reported cumulative incidence ; this finding is similar to an increase in positive COVID-19 tests demonstrated in HCW in the US and the United Kingdom compared to the general community in a study by Nguyen et al . who demonstrated a threefold increase in risk . 14 However , this finding is in stark contrast to earlier reports in New York City , which demonstrated lower rates in frontline workers . 15 Risks for HCW that were identified in a study by Gholami et al . included workplace setting such as nursing homes , PPE availability , hand hygiene habits , and other factors . 16
Positive antibody rates for CEW in Kanawha , Putnam , and Cabell counties were not statistically significant . Kanawha County HCW , however , had a positive rate of 12.1 % in our study . Although numerically higher than HCW of other counties , this was not
B
Positive Participant COVID-19 PCR
Negative Antibody
Figure 3A denotes results from participants reporting a suspicion of previously having COVID-19 infection . Figure 3B denotes results from participants reporting a positive COVID-19 PCR test before enrollment . statistically significant ( Putnam 3.5 %, Cabell 0 %, p = 0.06 ), but this difference does seem to drive the significance of positive tests from Kanawha County as a whole . The positive rate of Kanawha County HCW was also higher than Kanawha County CEW at 6.5 % and the reported Kanawha County cumulative rate in the general population at the time of 4.9 %. 2 There may have been an inherent risk factor in Kanawha County HCW that introduced bias in that specific population . Perhaps the risk factors were associated with the timing of testing , the specific patient population within Kanawha County hospitals , or differing safety protocols within the hospitals .
An unexpected finding regarding HCW was that working in a COVID-19 unit was not the driving factor , as we found no significant difference in antibody rates between workers with direct COVID-19 patient contact versus those who did not experience direct exposure . This result is inconsistent with our finding that participants with a known close exposure in any environment had a much higher risk of positive antibody results . A potential explanation is that healthcare workers assumed an inherent exposure risk and therefore had better adherence to standard infection prevention protocols , or perhaps did not contract COVID-19 from the patients they cared for while at work .
Our study had multiple limitations . Firstly , detectable COVID-19 IgG serum levels develop one to three weeks post-infection , which can create a false negative serum antibody result in those with a recent COVID infection . Secondly , at least one previous study included results that indicated that COVID-19 antibody levels wane over time to even undetectable levels , especially in those with mild illnesses . 17 This waning could account for the eight participants in our study who reported previously testing positive for COVID-19 but were found to have nonreactive antibody levels . Participants also volunteered to participate in our study after research enrollment flyers were posted in essential workforce locations such as hospitals , schools , retail establishments , and COVID testing centers . This recruitment method introduces intentional sampling bias and volunteer bias to the population studied , and therefore results may not accurately represent the general population .
CONCLUSION
This study confirms that healthcare workers had a much higher risk of contracting COVID-19 near Charleston , WV , during the initial wave of the pandemic . Despite ongoing exposure to the public , other essential workers such as grocery workers , teachers , and retail industries had similar rates of prior infection as measured by antibody tests compared to the general community as reported by the WV Department of Health . Known exposure to COVID-19 , prior testing for COVID-19 , and county of residence were risk factors for positive antibody tests ; whereas the timing of testing , living with others ( including children ), and working on a COVID-19 unit did not confer risk . With these findings , HCW may have been protected in direct patient care due to stringent safety guidelines . However , higher COVID-19 antibody rates are observed in HCW simply from the inherent risks of working in healthcare due to factors such as PPE use and habits , hand hygiene habits , sharing work culture , and roles or procedural areas within the hospital . Further evaluation of the habits and environments above as well as the interaction of vaccine protection would be of value .
West Virginia Medical Journal • June 2023 • 19