COVID-19 Diagnosis and SARS-CoV-2 Strain Identification by a Rapid, Multiplexed, Point-of-Care Antibody Microarray.

Antigen tests to detect SARS-CoV-2 have emerged as a promising rapid diagnostic method for COVID-19, but they are unable to differentiate between variants of concern (VOCs). Here, we report a rapid point-of-care test (POC-T), termed CoVariant-SPOT, that uses a set of antibodies that are either tolerant or intolerant to spike protein mutations to identify the likely SARS-CoV-2 strain concurrent with COVID-19 diagnosis using antibodies targeting the nucleocapsid protein. All reagents are incorporated into a portable, multiplexed, and sensitive diagnostic platform built upon a nonfouling polymer brush. To validate CoVariant-SPOT, we tested recombinant SARS-CoV-2 proteins, inactivated viruses, and nasopharyngeal swab samples from COVID-19 positive and negative individuals and showed that CoVariant-SPOT can readily distinguish between two VOCs: Delta and Omicron. We believe that CoVariant-SPOT can serve as a valuable adjunct to next-generation sequencing to rapidly identify variants using a scalable and deployable POC-T, thereby enhancing community surveillance efforts worldwide and informing treatment selection.

Effects of portable air cleaners and A/C unit fans on classroom concentrations of particulate matter in a non-urban elementary school.

Given the increased use of air cleaners as a prevention measure in classrooms during the COVID-19 pandemic, this study aimed to investigate the effects of portable air cleaners with HEPA filters and window A/C fans on real-time (1 minute) concentrations of PM less than 2.5 microns (PM2.5) or less than 1 microns (PM1.0) in two classrooms in a non-urban elementary school in Rhode Island. For half of each school day, settings were randomized to "high" or "low" for the air cleaner and "on" or "off" for the fan. Descriptive statistics and linear mixed models were used to evaluate the impacts of each set of conditions on PM2.5 and PM1.0 concentrations. The mean half-day concentrations ranged from 3.4-4.1 µg/m3 for PM2.5 and 3.4-3.9 µg/m3 for PM1.0. On average, use of the fan when the air cleaner was on the low setting decreased PM2.5 by 0.53 µg/m3 [95% CI: -0.64, -0.42] and use of the filter on high (compared to low) when the fan was off decreased PM2.5 by 0.10 µg/m3 [95% CI: -0.20, 0.005]. For PM1.0, use of the fan when the air cleaner was on low decreased concentrations by 0.18 µg/m3 [95% CI: -0.36, -0.01] and use of the filter on high (compared to low) when the fan was off decreased concentrations by 0.38 µg/m3 [95% CI: -0.55, -0.21]. In general, simultaneous use of the fan and filter on high did not result in additional decreases in PM concentrations compared to the simple addition of each appliance's individual effect estimates. Our study suggests that concurrent or separate use of an A/C fan and air cleaner in non-urban classrooms with low background PM may reduce classroom PM concentrations.

Effect of Immunosuppressive Diseases and Rituximab Infusions on Allowing COVID-19 Infection to Relapse.

INTRODUCTION: Relapsing COVID-19 infections have been reported, but their etiology and severity are still unknown. In addition, there have been no cases in the literature that associate relapsing infection with immunosuppression, either from a disease course or medications. CASE PRESENTATION: This case series illustrates two patients who developed a relapsed infection, likely from recent rituximab infusions. In addition, both cases depicted a severe form of infection than the initial one. Laboratory investigations revealed these patients were unable to produce COVID-19 antibodies, even though one of the patients received convalescent plasma. CONCLUSION: Clinicians should be aware of the possibility of relapsing COVID-19, especially in immunosuppressed patients. Because rituximab induces B-cell depletion, it can also decrease the effectiveness of the COVID-19 vaccine. Therefore, these patients should receive the vaccine before their scheduled rituximab infusion.

Dermatologic Manifestation of Acro-Ischemia Associated With COVID-19.

Background: The common dermatologic manifestations seen in patients with coronavirus disease 2019 (COVID-19) include morbilliform, pernio-like, urticarial, macular erythematous, vesicular, and papulosquamous disorders, as well as retiform purpura. Although cases of acro-ischemia have been demonstrated, they are not well studied or reported. Case Report: A 73-year-old male was admitted for acute hypoxic respiratory failure secondary to COVID-19 infection. During the patient's hospital course, his oxygen requirement progressively increased, and he developed painful, violaceous purpura on his right lower extremity digits. The patient was treated with therapeutic doses of enoxaparin and nitroglycerin ointment in the hospital and apixaban on discharge. The patient was lost to follow-up. Conclusion: The multiorgan dysfunction associated with COVID-19 includes dermatologic manifestations. This case illustrates that acro-ischemia can resolve with guideline-based medical treatment.

Multiplexed, quantitative serological profiling of COVID-19 from blood by a point-of-care test.

Highly sensitive, specific, and point-of-care (POC) serological assays are an essential tool to manage coronavirus disease 2019 (COVID-19). Here, we report on a microfluidic POC test that can profile the antibody response against multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens-spike S1 (S1), nucleocapsid (N), and the receptor binding domain (RBD)-simultaneously from 60 µl of blood, plasma, or serum. We assessed the levels of antibodies in plasma samples from 31 individuals (with longitudinal sampling) with severe COVID-19, 41 healthy individuals, and 18 individuals with seasonal coronavirus infections. This POC assay achieved high sensitivity and specificity, tracked seroconversion, and showed good concordance with a live virus microneutralization assay. We can also detect a prognostic biomarker of severity, IP-10 (interferon-γ-induced protein 10), on the same chip. Because our test requires minimal user intervention and is read by a handheld detector, it can be globally deployed to combat COVID-19.