Although it seems intuitive that the risks of infection in health workers would be higher among those treating COVID-19 patients, a large US study appears to refute this assumption.
Some data shows that the risk of COVID-19 infection is higher among health care workers and that this is mainly through exposure to infected patients although this finding is not consistent. For instance, one study of 734 health care workers observed that the incidence of COVID-19 seropositivity was no higher compared to those with limited or no exposure to infected patients. Hence, given this uncertainty, a team from the School of Medicine, Emory University, Atlanta, US, decided to further examine the potential risk factors among health care workers in four separate centres across the US. At each of the sites, all health care professionals (HCPs) were eligible to participate and provided samples for serological analysis. Data were collected on demographics (age, gender, ethnicity), known COVID-19 contacts in the community and the healthcare workplace role and potential for contact with infected patient. Workplace locations were categorised as emergency department, inpatient (irrespective of direct COVID-19 patient care), worked from home or unknown location. In addition, because COVID-19 care was captured slightly differently in the four sites, it was re-categorised as either “never” or providing “any COVID-19 care”. As well as self-reported COVID-19 community contact, the researchers assigned a zip code-based value of community exposure to COVID-19 based on the number cases nationally recorded for the zip code areas and linked this to the HCPs location.
Findings
A total of 24,749 HCPs with most (69.9%) under 50 years of age (78.2% female) and of White ethnicity (61.2%) provided data for analysis. The majority worked in acute care hospitals (87.1%) and half (50.2%) reported caring for patients with COVID-19 or working in a COVID-19 designated area. The incidence of COVID-19 in the community ranged from 8.2 cases per 10,000 to 275.6 cases per 10,000 and the overall seropositivity rate was for the sample was 4.4%. In adjusted regression analysis, community COVID-19 contact and a higher incidence of community COVID-19 incidence were most strongly associated with seropositivity. For instance, the adjusted odds ratio (OR) for community COVID-19 contact was 3.5 (95% CI 2.9 – 4.1) and 1.8 (95% CI 1.3 – 2.6) for community incidence. In addition, none of the workplace factors were associated with seropositivity.
The authors commented on how a strength of the study was that it included geographically diverse healthcare systems and how their results suggested an apparent lack of association between those factors presumed to be relevant to transmission, e.g., workplace role, caring for COVID-19 patients and seropositivity. In fact, seropositivity was more strongly associated with both community contact with COVID-19 and a higher community infection rate. They concluded that current infection control practices appear effective against transmission of the virus.
Citation
Jacob JT et al. Risk factors associated with SARS-CoV-2 seropositivity among US health care personnel. JAMA Netw Open 2021
