ABSTRACT
The vulnerability of healthcare and laboratory to potential infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has thus far been analyzed through the lens of the acute phase of the pandemic, including remote-based work, as well as emergency settings that are different from routine healthcare operations. However, as lockdowns ease and activities return to an identifiable pre-pandemic routine, the safety considerations also require to shift accordingly. As laboratory workers are likely to continue being exposed to unidentified SARS-CoV-2 positive samples through routine blood collection and processing operations, coronavirus disease 2019 (COVID-19) might have to be re-considered as an occupational disease within this context. Additionally, as per many such occupational diseases, a surveillance system is implemented for the medium- and long-term. This manuscript presents the views on the possible surveillance scenarios for laboratory staff, viewed from an immunological and biosafety perspective.
ABSTRACT
Serological testing of large representative populations for antibodies to SARS-CoV-2 is needed to estimate seroprevalence, transmission dynamics, and the duration of antibody responses from natural infection and vaccination. In this study, a high-throughput SARS-CoV-2 multiplex microsphere immunoassay (MMIA) was developed for the receptor binding domain (RBD) and nucleocapsid (N) that was more sensitive than enzyme-linked immunosorbent assay (ELISA) (98% versus 87%). The MMIA was then applied and validated in 264 first responders in Colorado using serum and dried blood spot (DBS) eluates, compared to ELISA, and evaluated for neutralizing antibodies. Four percent (11/264) of first responders were seropositive in July to August 2020. Serum and DBS were highly correlated for anti-RBD and anti-N antibodies (R = 0.83, P < 0.0001 and R = 0.87, P < 0.0001, respectively) by MMIA. The MMIA accurately predicted SARS-CoV-2 neutralizing antibodies using DBS (R = 0.76, P = 0.037). On repeat antibody testing 3 months later, anti-RBD IgG decreased less rapidly than anti-N IgG measured by MMIA, with a median change in geometric median fluorescence intensity of 62% versus 79% (P < 0.01) for anti-RBD and anti-N IgG, respectively. This novel MMIA using DBS could be scalable for rapid and affordable SARS-CoV-2 serosurveillance in the United States and globally.