Prevalence and Longevity of SARS-CoV-2 Antibodies Among Health Care Workers

Abstract

Background Understanding SARS-CoV-2 antibody prevalence in a spectrum of healthcare workers (HCWs) may provide benchmarks of susceptibility, help understand risk stratification, and support enactment of better health policies and procedures. Method Blood serum was sampled at enrollment and 8-week follow-up from HCWs (n=3,458) and from community first responders (n=226) for IgG analyses. Demographics, job duties, location, and COVID-19 related information were collected. Results Observed IgG antibody prevalence was 0.93% and 2.58% at enrollment (May/June) and 8-week follow-up (July/Aug), respectively, for HCWs, and 5.31% and 4.35% for first responders. For HCWs, significant differences (p < .05) between negative vs. positive at initial assessment were found for age, race, fever, and loss of smell, and at 8-week follow-up for age, race, and all symptoms. Antibody positivity persisted at least 8 weeks in all positive HCWs. Conclusions We found considerably lower antibody prevalence among HCWs compared to other published studies. While rigorous safety process measures instituted in our workplace and heightened awareness at and outside of the workplace among our HCWs may have contributed to our findings, the significant discrepancy from our community prevalence warrants further studies on other contributing factors.

Longevity of SARS-CoV-2 Antibody in Health Care Workers: 6-Months Follow Up

“…Our previous HCW sero-suvaillance studies have shown a low prevalence of antibodies ranging from 0.98% to 2.58% depending on sampling timing (e.g., before or after partial state re-opening in late May, 2020) [5,6]. Serology prevalence in HCWs was found to be loosely correlated with community prevalence [6].…”

“…Prior sero-suvaillance studies among HCWs have reported widely ranging antibody prevalence from 89.3% in Wuhan, China (n=424) [1], 35.8% in New York City (n=285) [2], to 7.4% in Milan, Italy [3], and 2.67% in Denmark (n=28,792) [4]. Our previous HCW sero-suvaillance studies have shown a low prevalence of antibodies ranging from 0.98% to 2.58% depending on sampling timing (e.g., before or after partial state re-opening in late May, 2020) [5,6]. Serology prevalence in HCWs was found to be loosely correlated with community prevalence [6].…”

“…IRB approval was obtained for this study (Providence St. Joseph Health IRB # 2020000337). The original HCWs cohort (n=3,458) was recruited by email notification to the entire employee workforce and medical staff [6]. Consenting participants were interviewed with regards to job duties, location, COVID-19 symptoms (i.e., fever, sore throat, cough, rhinorrhea, loss of taste or smell), PCR test history, travel record, and existence of household contacts with COVID-19.…”

Predictors of COVID‐19 Seropositivity Among Healthcare Workers: An Important Piece of an Incomplete Puzzle

“…A similar spillover effect has been hypothesized for low HCW seroprevalence relative to the surrounding community in California. 2 In complement, researchers at a large New York City (NYC) hospital found higher overall HCW seropositivity rates compared with the community, though estimates were strikingly variable after detailed stratification by job function and location. 3 The gradient of seroprevalence showed the highest risk among nurses and those in nonclinical, low-wage jobs (eg, patient transport, housekeeping), a finding also seen in another US study prior to adjustment for demographic and community factors.…”

“…6 Several studies comparing HCW to local community seropositivity rates have reached disparate conclusions. 2,7 These contrasting data may result from variability in vigilance of PPE use, mask use in work rooms or during meals/breaktimes, sick leave policies driven by staffing demands, and neighborhood factors. In addition, selection biases and timing of blood sampling relative to viral transmission peaks (with differing degrees of temporal antibody waning) may contribute to the apparent discordance.…”