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Topics in Antiviral Medicine ; 29(1):269-270, 2021.
Article in English | EMBASE | ID: covidwho-1250626


Background: Closing labs to decrease spread of COVID-19 has impacted research progress. Serial testing could supplement other measures to help provide a safe lab environment. Methods: Lab employees who came to work at an academic laboratory at the University of California San Diego (UCSD) were invited and consented to perform their own anterior nasal swab or have a swab collected by an on-site physician. Nasal swabs were combined into one pool for each work shift. Each pool underwent nucleic acid testing (NAT) via qRT-PCR to detect SARS-CoV-2 RNA (FluxErgy). Results were available within one hour. Positive pools were deconvoluted and tested individually. Cost evaluation of the pooling approach was compared to individual NAT and to institutional guidelines for lab occupancy. Results: From Apr 9 to Oct 26, 2020 (28 weeks), 1,199 nasal swab samples collected from lab workers were batched in 194 pools of median size 7 [95%I: 3-11]. A median of 41 tests per week [95%I: 22-67] were performed in a total of 77 participants (Fig 1). 19 core staff were tested a median 54 times [95%I:13-95]. Of the 194 pools, 7 (3.6%, n=47 samples) were considered positive and required repeat testing of all participant samples in the pool as confirmation. One true positive was identified before work started. That participant was referred to their primary care provider. This early detection prevented a 2-week quarantine of 7 employees. Given ∼$65/hour salary per lab worker, this saved 420 hours of work and ∼$26,600 in wages. Current UCSD guidelines recommend decreasing staffing levels to 25% of pre-COVID-19 occupancy. Regular NAT allowed 100% staffing. Screening of lab technicians with the pooled NAT strategy over 6 months cost $25,740 but permitted 2,430 person-hours of additional work ($132,210 in wages), as compared to the recommended 75% reduction without testing. A similar approach with individual NAT would cost $124,020 (thus $98,280 saved by pooling). Conclusion: Regular pooled NAT for SARS-CoV-2 among lab personnel offers a cost-efficient way to maintain a safe lab environment without a reduction in staffing. This approach could be applied in other settings to help ensure safe work environments.

Journal of Infectious Diseases ; 222(2):206-213, 2020.
Article in English | MEDLINE | ID: covidwho-618807


BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), is associated with respiratory-related disease and death. Assays to detect virus-specific antibodies are important to understand the prevalence of infection and the course of the immune response. METHODS: Quantitative measurements of plasma or serum antibodies to the nucleocapsid and spike proteins were analyzed using luciferase immunoprecipitation system assays in 100 cross-sectional or longitudinal samples from patients with SARS-CoV-2 infection. A subset of samples was tested both with and without heat inactivation. RESULTS: At 14 days after symptom onset, antibodies against SARS-CoV-2 nucleocapsid protein showed 100% sensitivity and 100% specificity, whereas antibodies to spike protein were detected with 91% sensitivity and 100% specificity. Neither antibody levels nor the rate of seropositivity were significantly reduced by heat inactivation of samples. Analysis of daily samples from 6 patients with COVID-19 showed anti-nucleocapsid and spike protein antibodies appearing between days 8 and 14 after initial symptoms. Immunocompromised patients generally had a delayed antibody response to SARS-CoV-2, compared with immunocompetent patients. CONCLUSIONS: Antibody to the nucleocapsid protein of SARS-CoV-2 is more sensitive than spike protein antibody for detecting early infection. Analyzing heat-inactivated samples with a luciferase immunoprecipitation system assay is a safe and sensitive method for detecting SARS-CoV-2 antibodies.