Prevalence of Current and Past SARS-CoV-2 Infections among Police Employees in Poland, June-July 2020
JOURNAL OF CLINICAL MEDICINE
Authors: Gujski, Mariusz; Jankowski, Mateusz; Pinkas, Jaroslaw; Wierzba, Waldemar; Samel-Kowalik, Piotr; Zaczynski, Artur; Jedrusik, Piotr; Pankowski, Igor; Juszczyk, Grzegorz; Rakocy, Kamil; Raciborski, Filip
Abstract
Background: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to determine the prevalence of current and past SARS-CoV-2 infections among police employees. Methods: This cross-sectional survey was undertaken among 5082 police employees from Mazowieckie Province, Poland. RT-PCR testing for current SARS-CoV-2 infection and serological tests (ELISA) for the presence of anti-SARS-CoV-2 IgM+IgA and IgG antibodies were performed. Results: All RT-PCR tests were negative. The anti-SARS-CoV-2 IgM+IgA index was positive (>8) in 8.9% of participants, including 11.2% women and 7.7% men (p < 0.001). Equivocal IgM+IgA index (6-8) was found in 9.8% of participants, including 11.9% women and 8.7% men (p < 0.001). The IgG index was positive (>6) in 4.3% and equivocal (4-6) in 13.2% of participants. A higher odds of positive IgM+IgA index was found in women vs. men (OR: 1.742) and police officers vs. civilian employees (OR: 1.411). Participants aged >= 60 years had a higher odds of positive IgG index vs. those aged 20-29 years (OR: 3.309). Daily vaping also increased the odds of positive IgG index (OR: 2.058). Conclusions: The majority of Polish police employees are seronegative for SARS-CoV-2 infection. Vaping and older age (>= 60 years) were associated with a higher risk of SARS-CoV-2 infection.
Lateral flow assay modified with time-delay wax barriers as a sensitivity and signal enhancement strategy
BIOSENSORS & BIOELECTRONICS
Authors: Sena-Torralba, Amadeo; Duy Ba Ngo; Parolo, Claudio; Hu, Liming; Alvarez-Diduk, Ruslan; Francisco Bergua, Jose; Rosati, Giulio; Surareungchai, Werasak; Merkoci, Arben
Abstract
The ease of use, low cost and quick operation of lateral flow assays (LFA) have made them some of the most common point of care biosensors in a variety of fields. However, their generally low sensitivity has limited their use for more challenging applications, where the detection of low analytic concentrations is required. Here we propose the use of soluble wax barriers to selectively and temporarily accumulate the target and label nanoparticles on top of the test line (TL). This extended internal incubation step promotes the formation of the immune-complex, generating a 51.7-fold sensitivity enhancement, considering the limit of quantification, and up to 96% signal enhancement compared to the conventional LFA for Human IgG (H-IgG) detection.
COA
Publication 
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