Salivette® Cortisol versus oropharyngeal swabbing for the detection of SARS-CoV-2 infection.

BACKGROUND: Detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by naso/oropharyngeal swabbing may expose health-care workers to the virus and is technically challenging. The Salivette® is an alternative saliva-collection device with an oral cotton swab containing citric acid to stimulate saliva production, which may have an unpleasant taste. We present a pilot study comparing the Salivette® Cortisol (SC), which uses a synthetic swab without citric acid, against oropharyngeal swabbing for the detection of SARS-CoV-2 by reverse transcription quantitative polymerase chain reaction (RT-qPCR). RESEARCH DESIGN AND METHODS: Symptomatic SARS-CoV-2-positive patients were sampled at various timepoints. The number of patients positive/negative for SARS-CoV-2 in oropharyngeal swab and SC samples and the percentage of patients testing true positive/true negative for SARS-CoV-2 from SC samples were determined. Positivity was defined by RT-qPCR amplification of 2/3 target SARS-CoV-2 N, ORF1, and S gene sequences. RESULTS: SC demonstrated 100% specificity, 52.2% sensitivity, and positive correlation with oropharyngeal swabbing for the detection of the SARS-CoV-2 S gene. In later-stage disease, lower viral load was observed in SC samples compared with oropharyngeal swabs. CONCLUSIONS: The SC may be an alternative for SARS-CoV-2 detection where naso/oropharyngeal swabbing is not feasible/available. This technique also confirms observations that the detection of SARS-CoV-2 in the upper airway may vary due to viral load over the disease course. TRIAL REGISTRATION: NCT04599959.

High Expression Levels of miR-21-5p in Younger Hospitalized COVID-19 Patients Are Associated with Mortality and Critical Disease.

In COVID-19, critical disease and invasive mechanical ventilation (IMV) increase the risk of death, mainly in patients over 60 years of age. OBJECTIVES: To find the relationship between miR-21-5p and miR-146a-5p in terms of the severity, IMV, and mortality in hospitalized COVID-19 patients younger than 55 years of age. METHODS: The patients were stratified according to disease severity using the IDSA/WHO criteria for severe and critical COVID-19 and subclassified into critical non-survivors and critical survivors. RESULTS: Ninety-seven severe/critical COVID-19 patients were included; 81.3% of the deceased were male and 18.8% were female. Higher expression miR-21-5p levels were associated as follows: severe vs. critical disease (p = 0.007, FC = 0.498), PaO2/FiO2 index, mild vs. severe (p = 0.027, FC = 0.558), and survivors vs. non-survivors (p = 0.03, FC = 0.463). Moreover, we identified correlations with clinical variables: CRP (rho = -0.54, p < 0.001), D-dimer (rho = -0.47, p < 0.05), related to damage in the kidney (rho = 0.60, p < 0.001), liver (rho = 0.41, p < 0.05), and lung (rho = 0.54, p < 0.001). Finally, miR-21-5p thresholds were calculated according to severity (8.191), IMV (8.191), and mortality (8.237); these values increased the risk of developing a critical disease (OR = 4.19), the need for IMV (OR = 5.63), and death (OR = 6.00). CONCLUSION: Increased expression levels of miR-21-5p are related to worse outcome of COVID-19 in younger hospitalized patients.

Expression of Surfactant Protein D Distinguishes Severe Pandemic Influenza A(H1N1) from Coronavirus Disease 2019.

The differentiation between influenza and coronavirus disease 2019 (COVID-19) could constitute a diagnostic challenge during the ongoing winter owing to their clinical similitude. Thus, novel biomarkers are required to enable making this distinction. Here, we evaluated whether the surfactant protein D (SP-D), a collectin produced at the alveolar epithelium with known immune properties, was useful to differentiate pandemic influenza A(H1N1) from COVID-19 in critically ill patients. Our results revealed high serum SP-D levels in patients with severe pandemic influenza but not those with COVID-19. This finding was validated in a separate cohort of mechanically ventilated patients with COVID-19 who also showed low plasma SP-D levels. However, plasma SP-D levels did not distinguish seasonal influenza from COVID-19 in mild-to-moderate disease. Finally, we found that high serum SP-D levels were associated with death and renal failure among severe pandemic influenza cases. Thus, our studies have identified SP-D as a unique biomarker expressed during severe pandemic influenza but not COVID-19.

SARS-CoV-2 Direct Detection Without RNA Isolation With Loop-Mediated Isothermal Amplification (LAMP) and CRISPR-Cas12.

As to date, more than 49 million confirmed cases of Coronavirus Disease 19 (COVID-19) have been reported worldwide. Current diagnostic protocols use qRT-PCR for viral RNA detection, which is expensive and requires sophisticated equipment, trained personnel and previous RNA extraction. For this reason, we need a faster, direct and more versatile detection method for better epidemiological management of the COVID-19 outbreak. In this work, we propose a direct method without RNA extraction, based on the Loop-mediated isothermal amplification (LAMP) and Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated protein (CRISPR-Cas12) technique that allows the fast detection of SARS-CoV-2 from patient samples with high sensitivity and specificity. We obtained a limit of detection of 16 copies/µL with high specificity and at an affordable cost. The diagnostic test readout can be done with a real-time PCR thermocycler or with the naked eye in a blue-light transilluminator. Our method has been evaluated on a small set of clinical samples with promising results.