ABSTRACT
Background: Identifying factors associated with SARS-CoV-2 infection among healthcare workers (HCW)s may help health systems optimize SARS-CoV-2 infection control strategies. Methods: We conducted a cross-sectional analysis of baseline data from the Northwestern HCW SARS-CoV-2 Serology Cohort Study. The Abbott Architect Nucleocapsid IgG assay was used to determine seropositivity. Logistic regression models (unadjusted and adjusted for demographics and self-reported community exposure to COVID-19) were fit to quantify the associations between occupation group, healthcare delivery tasks, and community exposure and seropositive status. Results: 6,510 HCWs, including 1,794 nurses, and 904 non-patient facing administrators participated. The majority were women (79.6%), 74.9% were white, 9.7% were Asian, 7.3% were Hispanic and 3.1% were Black. The crude prevalence rate of seropositivity was 4.8% (95% confidence interval (CI): 4.6%-5.2%). Out-of-hospital exposure to COVID-19 occurred in 9.3% of HCWs and was strongly associated with seropositivity (OR=4.7, 95% CI: 3.5-6.4). When compared to administrators, nursing was the only occupation group with a significantly higher adjusted-odds (OR: 1.9, 95% CI: 1.3-2.9) of seropositivity. Exposure to COVID-19 patients was reported by 37.8% of participants and was associated with higher positivity than those not exposed (OR= 2.2, 95% CI: 1.6-3.0). Being exposed to patients receiving high-flow oxygen therapy, and hemodialysis also remained significantly associated with a 45% and 57% higher odds for seropositive status, respectively. Conclusions: Exposure to COVID-19 patients, and longer duration patient therapies were each associated with higher risk for seropositive status; however, the community burden of COVID-19 remains a significant source of exposure to SARS CoV-2 infection among HCWs in Chicago.
ABSTRACT
We report dynamics of seroconversion to SARS-CoV-2 infections detected by IgG ELISA in 177 individuals diagnosed by RT-PCR. Longitudinal analysis identifies 2-8.5% of individuals who do not seroconvert even weeks after infection. They are younger than seroconverters who have increased co-morbidity and higher inflammatory markers such as C-Reactive Protein. Higher antibody responses are associated with non-white ethnicity. Antibody responses do not decline during follow up almost to 2 months. Serological assays increase understanding of disease severity. Their application in regular surveillance will clarify the duration and protective nature of humoral responses to SARS-CoV-2.
ABSTRACT
Here we describe an open and transparent consortium for the rapid development of COVID-19 rapid diagnostics tests. We report diagnostic accuracy data on the Mologic manufactured IgG COVID-19 ELISA on known positive serum samples and on a panel of known negative respiratory and viral serum samples pre-December 2019. In January, Mologic, embarked on a product development pathway for COVID-19 diagnostics focusing on ELISA and rapid diagnostic tests (RDTs), with anticipated funding from Wellcome Trust and DFID. 834 clinical samples from known COVID-19 patients and hospital negative controls were tested on Mologics IgG ELISA. The reported sensitivity on 270 clinical samples from 124 prospectively enrolled patients was 94% (95% CI: 89.60% - 96.81%) on day 10 or more post laboratory diagnosis, and 96% (95% CI: 84.85% - 99.46%) between 14-21 days post symptom onset. A specificity panel comprising 564 samples collected pre-December 2019 were tested to include most common respiratory pathogens, other types of coronavirus, and flaviviruses. Specificity in this panel was 97% (95% CI: 95.65% - 98.50%). This is the first in a series of Mologic products for COVID-19, which will be deployed for COVID-19 diagnosis, contact tracing and sero-epidemiological studies to estimate disease burden and transmission with a focus on ensuring access, affordability, and availability to low-resource settings.
