No abstract

Reliable serological tests are required to determine the prevalence of antibodies against SARS-CoV-2 and to characterise immunity to the disease in order to address key knowledge gaps in the COVID-19 pandemic. Quantitative suspension array technology (qSAT) assays based on the xMAP Luminex platform overcome the limitations of rapid diagnostic tests and ELISA with their higher precision, dynamic range, throughput, miniaturization, cost-efficacy and multiplexing capacity. We developed three qSAT assays for IgM, IgA and IgG to a panel of eight SARS-CoV-2 antigens including spike (S), nucleoprotein (N) and membrane (M) protein constructs. The assays were optimized to minimize processing time and maximize signal to noise ratio. We evaluated their performance using 128 pre-pandemic plasmas (negative controls) and 104 plasmas from individuals with SARS-CoV-2 diagnosis (positive controls), of whom 5 were asymptomatic, 51 had mild symptoms and 48 were hospitalized. Pre-existing IgG antibodies recognizing N, M and S proteins were detected in negative controls suggestive of cross-reactive to common cold coronaviruses. The best performing antibody/antigen signatures had specificities of 100% and sensitivities of 95.78% at ≥14 days and 95.65% at ≥21 days since the onset of symptoms, with AUC of 0.977 and 0.999, respectively. Combining multiple markers as assessed by qSAT assays has the highest efficiency, breadth and versatility to accurately detect low-level antibody responses for obtaining reliable data on prevalence of exposure to novel pathogens in a population. Our assays will allow gaining insights into antibody correlates of immunity and their kinetics, required for vaccine development to combat the COVID-19 pandemic.

COVID-19 patients elicit strong responses to the nucleocapsid (N) protein of SARS-CoV-2 but binding antibodies are also detected in prepandemic individuals, indicating potential crossreactivity with common cold human coronaviruses (HCoV) and questioning its utility in seroprevalence studies. We investigated the immunogenicity of the full-length and shorter fragments of the SARS-CoV-2 N protein, and the crossreactivity of antibodies with HCoV. We identified a C-terminus region in SARS-CoV2 N of minimal sequence homology with HCoV that was more specific for SARS-CoV-2 and highly immunogenic. IgGs to the full-length SARS-CoV-2 N also recognized N229E N, and IgGs to HKU1 N recognized SARS-CoV-2 N. Crossreactivity with SARS-CoV-2 was stronger for alpha-rather than beta-HCoV despite having less sequence identity, revealing the importance of conformational recognition. Higher preexisting IgG to OC43 N correlated with lower IgG to SARS-CoV-2 N in rRT-PCR negative individuals, reflecting less exposure and indicating a potential protective association. Antibodies to SARS-CoV-2 N were higher in patients with more severe and longer duration of symptoms and in females. IgGs remained stable for at least 3 months, while IgAs and IgMs declined faster. In conclusion, N protein is a primary target of SARS-CoV-2-specific and HCoV crossreactive antibodies, both of which may affect the acquisition of immunity to COVID-19.

Reliable serological tests are required to determine the prevalence of antibodies against SARS-CoV-2 antigens and to characterise immunity to the disease in order to address key knowledge gaps in the context of the COVID-19 pandemic. Quantitative suspension array technology (qSAT) assays based on the xMAP Luminex platform overcome the limitations of rapid diagnostic tests and ELISA with their higher precision, dynamic range, throughput, miniaturization, cost-efficacy and multiplexing capacity. We developed three qSAT assays to detect IgM, IgA and IgG to a panel of eight SARS-CoV-2 antigens including spike (S), nucleoprotein (N) and membrane (M) protein constructs. The assays were optimized to minimize processing time and maximize signal to noise ratio. We evaluated the performance of the assays using 128 plasmas obtained before the COVID-19 pandemic (negative controls) and 115 plasmas from individuals with SARS-CoV-2 diagnosis (positive controls), of whom 8 were asymptomatic, 58 had mild symptoms and 49 were hospitalized. Pre-existing IgG antibodies recognizing N, M and S2 proteins were detected in negative controls suggestive of cross-reactive to common cold coronaviruses. The best performing antibody isotype/antigen signatures had specificities of 100% and sensitivities of 94.94% at ≥14 days since the onset of symptoms and 96.08% at ≥21 days since the onset of symptoms, with AUC of 0.992 and 0.999, respectively. Combining multiple antibody markers as assessed by qSAT assays has the highest efficiency, breadth and versatility to accurately detect low-level antibody responses for obtaining reliable data on prevalence of exposure to novel pathogens in a population. Our assays will allow gaining insights into antibody correlates of immunity required for vaccine development to combat pandemics like the COVID-19.

Thrombophylaxis with low molecular weight heparin (LMWH) in hospitalized patients with COVID-19 is mandatory, unless contraindicated. Given the links between inflammation and thrombosis, the use of higher doses of anticoagulants could improve outcomes. We conducted an open-label, multicenter, randomized, controlled trial in adult patients hospitalized with non-severe COVID-19 pneumonia and elevated D-dimer. Patients were randomized to therapeutic-dose bemiparin (115 IU/Kg daily) vs. standard prophylaxis (bemiparin 3,500 IU daily), for 10 days. The primary efficacy outcome was a composite of death, intensive care unit admission, need of mechanical ventilation support, development of moderate/severe acute respiratory distress and venous or arterial thrombosis within 10 days of enrollment. The primary safety outcome was major bleeding (ISTH criteria). A prespecified interim analysis was performed when 40% of the planned study population was reached. From October 2020 to May 2021, 70 patients were randomized at 5 sites and 65 were included in the primary analysis; 32 patients allocated to therapeutic-dose and 33 to standard prophylactic-dose. The primary efficacy outcome occurred in 7 patients (21.9%) in the therapeutic-dose group and 6 patients (18.2%) in the prophylactic-dose (absolute risk difference 3.6% [95% CI, -16%- 24%]; odds ratio 1.26 [95% CI, 0.37-4.26]; p=0.95). Discharge in the first 10 days was possible in 66% and 79% of patients, respectively. No major bleeding event was registered. Therefore, in patients with COVID-19 hospitalized with non-severe pneumonia but elevated D-dimer, the use of a short course of therapeutic-dose bemiparin did not improve clinical outcomes compared to standard prophylactic doses.

Objective: To study the association between adherence to several a priori-defined healthy food patterns and the risk of hypertension. Design: Prospective, multipurpose, dynamic cohort study (recruitment permanently open). We followed up 10 800 men and women (all of them university graduates), who were initially free of hypertension, for a variable period (range 2-6 years, median 4?6 years). During follow-up, 640 participants reported a new medical diagnosis of hypertension. Baseline diet was assessed using a validated 136-item FFQ. Validated information about non-dietary potential confounders was also gathered. We calculated adherence to fifteen different hypothesisoriented food patterns and assessed the association between each of them and incident hypertension using multivariable Cox models. Setting: The SUN (Seguimiento Universidad de Navarra -University of Navarra Follow-up) Project, Spain. Subjects: Participants recruited to the SUN cohort before October 2005 were eligible for inclusion; after excluding those with self-reported hypertension or CVD at baseline, or with extreme total energy intake, data of 10 800 were analysed. Results: Higher adherence to the DASH (Dietary Approaches to Stop Hypertension) diet (range of the score: 0 to 5) was significantly associated with a lower risk for developing hypertension (P for trend 5 0?02). The other food patterns showed no significant association with incident hypertension. Conclusions: Our results support a long-term protection of the DASH diet against the incidence of hypertension, but we found no evidence of a similar inverse association with hypertension for any other a priori-defined healthy food pattern.

Objective: To describe the association between alcohol beverage preference and dietary habits comparing wine drinkers with other alcoholic beverage drinkers and with nondrinkers in Spanish university graduates. Subjects: A total of 10 526 men and women, who were recruited using mailed questionnaires, participated in this study. Methods: A semiquantitative food frequency questionnaire previously validated in Spain was used together with other questionnaires designed to collect lifestyle characteristics. Results: Wine drinkers reported higher intake of fibre and olive oil, and lower consumption of fat (only men), dairy products, sugared soda drinks and fast food as compared with other alcoholic beverage groups and nondrinkers. Men nondrinkers were more likely to be physically active during their leisure time than wine drinkers. No relevant differences were found in adherence to the Mediterranean food pattern according to alcoholic beverage preference. Conclusion: This similarity in dietary patterns between wine drinkers and other groups suggests that the positive cardiovascular effects reported for wine should not be attributed to an overall healthier dietary pattern of wine drinkers.

IntroductionOn March 11, 2020, the World Health Organization sounded the COVID-19 pandemic alarm. While efforts in the first few months focused on reducing the mortality of infected patients, there is increasing data on the effects of long-term infection (Post-COVID-19 condition). Among the different symptoms described after acute infection, those derived from autonomic dysfunction are especially frequent and limiting.ObjectiveTo conduct a narrative review synthesizing current evidence of the signs and symptoms of dysautonomia in patients diagnosed with COVID-19, together with a compilation of available treatment guidelines.ResultsAutonomic dysfunction associated with SARS-CoV-2 infection occurs at different temporal stages. Some of the proposed pathophysiological mechanisms include direct tissue damage, immune dysregulation, hormonal disturbances, elevated cytokine levels, and persistent low-grade infection. Acute autonomic dysfunction has a direct impact on the mortality risk, given its repercussions on the respiratory, cardiovascular, and neurological systems. Iatrogenic autonomic dysfunction is a side effect caused by the drugs used and/or admission to the intensive care unit. Finally, late dysautonomia occurs in 2.5% of patients with Post-COVID-19 condition. While orthostatic hypotension and neurally-mediated syncope should be considered, postural orthostatic tachycardia syndrome (POTS) appears to be the most common autonomic phenotype among these patients. A review of diagnostic and treatment guidelines focused on each type of dysautonomic condition was done.ConclusionSymptoms deriving from autonomic dysfunction involvement are common in those affected by COVID-19. These symptoms have a great impact on the quality of life both in the short and medium to long term. A better understanding of the pathophysiological mechanisms of Post-COVID manifestations that affect the autonomic nervous system, and targeted therapeutic management could help reduce the sequelae of COVID-19, especially if we act in the earliest phases of the disease.