Comparison between mid-nasal swabs and buccal swabs for SARS-CoV-2 detection in mild COVID-19 patients

BackgroundThe use of rapid antigen diagnostics tests (Ag-RDT) has gained widespread acceptance as an alternative method for diagnosis of COVID-19 outside of health care settings. Various authors have reported that saliva is a reliable specimen, alternative to nasopharyngeal and mid-nasal swabs, to detect SARS-CoV-2 infections by RT-PCR. We assessed the performance of buccal swabs containing saliva for SARS-CoV-2 detection by Ag-RDT, using mid-nasal specimens as a reference in the northern area of Barcelona (Catalonia, Spain) MethodsIn the context of routine clinical diagnosis of mild COVID-19 patients, we enrolled 300 adults in a study to directly compare mid-nasal swabs and saliva specimens for SARS-CoV-2 detection by Ag-RDT.. When mid-nasal and buccal Ag-RDTs showed discordant results, a third mid-nasal swab was collected and analysed by RT-PCR. ResultsPaired samples were successfully obtained in 300 suspected cases of SARS-CoV-2 infection. Of the 300 paired samples, Ag-RDT with the mid-nasal swab detected 139 (46.3%) positive COVID-19 cases. In comparison, buccal swabs showed a sensitivity and specificity of 31.7% (44/139) and 98.8% (159/161), respectively. 65 discordant results with positive mid-nasal swabs and negative buccal swabs were tested by RT-qPCR. All samples tested by Rt-PCR resulted positive, with a mean cycle threshold (Ct) of 28.3 (SD 7.3). ConclusionOur findings show that mid-nasal swabs have better performance than buccal swabs for detecting SARS-CoV-2 with Ag-RDT tests. Of note, the sensitivity of buccal samples was affected in samples with high viral loads (Ct<33), suggesting that buccal swabs might not be sensitive enough to detect individuals at risk of transmission. Taken together, the existing literature and the results provided in our analysis we advise against the use of buccal specimens for SARS-CoV-2 diagnostics with Ag-RDT.

Antibody kinetics to SARS-CoV-2 at 13.5 months, by disease severity

BackgroundUnderstanding humoral responses and seroprevalence in SARS-CoV-2 infection is essential for guiding vaccination strategies in both infected and uninfected individuals. MethodsWe determine the kinetics of IgM against the nucleocapsid (N) and IgG against the spike (S) and N proteins of SARS-CoV-2 in a cohort of 860 health professionals (healthy and infected) in northern Barcelona. We model the kinetics of IgG and IgM at nine time points over 13.5 months from infection, using non-linear mixed models by sex and clinical disease severity. ResultsOf the 781 participants who were followed up, 478 (61.2%) became infected with SARS-CoV-2. Significant differences were found for the three antibodies by disease severity and sex. At day 270 after diagnosis, median IgM(N) levels were already below the positivity threshold in patients with asymptomatic and mild-moderate disease, while IgG(N, S) levels remained positive to days 360 and 270, respectively. Kinetic modelling showed a general rise in both IgM(N) and IgG(N) levels up to day 30, followed by a decay whose rate depended on disease severity. IgG(S) levels increased at day 15 and remained relatively constant over time. ConclusionsWe describe kinetic models of IgM(N) and IgG(N, S) SARS-CoV-2 antibodies at 13.5 months from infection and disease spectrum. Our analyses delineate differences in the kinetics of IgM and IgG over a year and differences in the levels of IgM and IgG as early as 15 days from symptoms onset in severe cases. These results can inform public health policies around vaccination criteria. Funded by the regional Ministry of Health of the Generalitat de Catalunya (Call COVID19-PoC SLT16_04; NCT04885478)

Structural integrity of the contralesional hemisphere predicts cognitive impairment in ischemic stroke at three months.

After stroke, white matter integrity can be affected both locally and distally to the primary lesion location. It has been shown that tract disruption in mirror's regions of the contralateral hemisphere is associated with degree of functional impairment. Fourteen patients suffering right hemispheric focal stroke (S) and eighteen healthy controls (HC) underwent Diffusion Weighted Imaging (DWI) and neuropsychological assessment. The stroke patient group was divided into poor (SP; n = 8) and good (SG; n = 6) cognitive recovery groups according to their cognitive improvement from the acute phase (72 hours after stroke) to the subacute phase (3 months post-stroke). Whole-brain DWI data analysis was performed by computing Diffusion Tensor Imaging (DTI) followed by Tract Based Spatial Statistics (TBSS). Assessment of effects was obtained computing the correlation of the projections on TBSS skeleton of Fractional Anisotropy (FA) and Radial Diffusivity (RD) with cognitive test results. Significant decrease of FA was found only in right brain anatomical areas for the S group when compared to the HC group. Analyzed separately, stroke patients with poor cognitive recovery showed additional significant FA decrease in several left hemisphere regions; whereas SG patients showed significant decrease only in the left genu of corpus callosum when compared to the HC. For the SG group, whole brain analysis revealed significant correlation between the performance in the Semantic Fluency test and the FA in the right hemisphere as well as between the performance in the Grooved Pegboard Test (GPT) and the Trail Making Test-part A and the FA in the left hemisphere. For the SP group, correlation analysis revealed significant correlation between the performance in the GPT and the FA in the right hemisphere.

Factores de riesgo asociados a la presencia de hígado graso no alcohólico: un estudio de casos y controles / Risk factors associated with non-alcoholic fatty liver disease: A case-control study

Fundamento y objetivos: Establecer los factores asociados a la presencia de hígado graso no alcohólico (HGNA) y evaluar la influencia de cada uno de los componentes que forman el síndrome metabólico (SM) y el riesgo de padecer HGNA. Pacientes y método: Estudio analítico observacional de casos y controles, multicéntrico y de base poblacional. Se define como caso todos aquellos pacientes que cumplan los criterios de inclusión y presenten un HGNA mediante la práctica de una ecografía abdominal realizada por cualquier motivo. Para cada caso se selecciona un control al azar del mismo centro de salud, de la misma edad y sexo. A todos los casos se les realizó una anamnesis, exploración física, analítica completa y la determinación del SM según los criterios del National Cholesterol Education Program-Adult Treatment Panel III. A los controles se les practicó además una ecografía abdominal. Resultados:Se incluyeron 327 casos y 377 controles. La edad media (DE) fue de 56 (12) años en los casos y de 55 (13) años en los controles (extremos 17-80 años). El porcentaje de varones en los grupos de casos y controles, fue del 52,0 y 49,1%, respectivamente. Los factores de riesgo asociados a HGNA fueron la obesidad (odds ratio [OR] 3,82, intervalo de confianza del 95% [IC 95%] 2,19-6,66), SM (OR 1,73, IC 95% 1,09-2,75), resistencia a la insulina (OR 3,65, IC 95% 2,18-6,12), aumento de la alanino aminotransferasa (ALT) (OR 4,72, IC 95% 2,58-8,61) y gamma glutamil transferasa (GGT) (OR 1,95, IC 95% 1,14-3,34). Los componentes del SM que predicen mejor el HGNA fueron la hiperglucemia (OR 1,65, IC 95% 1,06-2,56) y los triglicéridos (OR 1,75, IC 95% 1,13-2,72). Conclusiones: Las variables independientes asociadas a HGNA son la obesidad, la resistencia a la insulina y valores de ALT y GGT elevados. Los componentes del SM que mejor predicen el HGNA son la hiperglucemia y el aumento de los triglicéridos (AU)

Background and objectives: To establish the factors associated with the presence of non-alcoholic fatty liver disease (NAFLD) and evaluate the influence of each component constituting the metabolic syndrome (MS) and the risk of developing NAFLD. Patients and methods: We performed a multicenter, population-based, observational, analytical study of cases and controls. A case was defined as any patient fulfilling the inclusion criteria and presenting NAFLD by abdominal echography for any reason. A control was randomly selected for each case, from the same health center and of the same age and sex. All the cases underwent anamnesis, physical examination, complete biochemical analyses and determination of MS according to the National Cholesterol Education Program-Adult Treatment Panel III criteria. All the controls also underwent an abdominal echography. Results: We included 327 cases and 377 controls with a mean age of 56 ± 12 years for the cases and of 55 ± 13 years for the controls (range: 17 and 80 years); 52.0% of the cases were males and 49.1% of males were controls. The risk factors associated with NAFLD were obesity (odds ratio [OR] 3.82, 95% confidence interval [95% CI] 2.19-6.66), MS (OR 1.73, 95% CI 1.09-2.75), insulin resistance (OR 3.65, 95% CI 2.18-6.12), and an increase in alanine aminotransferase (ALT) (OR 4.72, 95% CI 2.58-8.61) and gamma glutamyl transferase values (GGT) (OR 1.95, 95% CI 1.14-3.34). The components of the MS best predicting NAFLD were hyperglycemia (OR 1.65, 95% CI1.06-2.56) and triglyceride values (OR 1.75, 95% CI1.13-2.72). Conclusions: The independent variables associated with NAFLD were obesity, insulin resistance and elevated ALT and GGT. The components of MS best predicting NAFLD were hyperglycemia and an increase in triglyceride values (AU)