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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), etiological agent for the coronavirus disease 2019 (COVID-19), has resulted in over 775 million global infections. Early diagnosis remains pivotal for effective epidemiological surveillance despite the availability of vaccines. Antigen-based assays are advantageous for early COVID-19 detection due to their simplicity, cost-effectiveness, and suitability for point-of-care testing (PoCT). This study introduces a graphene field-effect transistor-based biosensor designed for high sensitivity and rapid response to the SARS-CoV-2 spike protein. By functionalizing graphene with monoclonal antibodies and applying short-duration gate voltage pulses, we achieve selective detection of the viral spike protein in human serum within 100  µ s and at concentrations as low as 1 fg ml -1 , equivalent to 8 antigen molecules per µ l of blood. Furthermore, the biosensor estimates spike protein concentrations in serum from COVID-19 patients. Our platform demonstrates potential for next-generation PoCT antigen assays, promising fast and sensitive diagnostics for COVID-19 and other infectious diseases., (Creative Commons Attribution license.)

Introduction: Severe forms of COVID-19, the disease caused by SARS-CoV-2, are characterized by acute respiratory distress syndrome, robust lung inflammation and death in some patients. Strong evidence has been accumulating that polymorphonuclear neutrophilic granulocytes (PMN) play an important role in the pathophysiology of severe COVID-19. SARS-CoV-2 directly induces in vitro PMN activation, mainly the release of neutrophil extracellular traps (NETs). However, the viral components inducing this PMN response remain unclear., Methods: In this work human PMN responses were assessed in vitro in response to the spike (S) protein of two different SARS-CoV-2 variants, anti-S IgG1 antibodies or immune complexes formed by them. Production of reactive oxygen species (ROS) was measured by Diogenes-based chemiluminescence. Release of myeloperoxidase (MPO) was assessed by ELISA while secretion of a list of cytokines and growth factors was determined by high-performance multiplex cytokine assay., Results and Discussion: We show that the SARS-CoV-2 Omicron variant S protein and anti-spike IgG1, either alone or together, stimulate ROS production in human PMNs. We also observed that the SARS-CoV-2 Wuhan S protein and anti-S IgG1 antibody together trigger MPO release from PMNs. Based on the relevance of SARS-CoV-2 and influenza co-infections, we have also investigated the impact of influenza virus infection on the previous PMN responses to S proteins or anti-S antibodies. We did not detect any significant effect of influenza co-infection on ROS generation in PMNs. Our data also show that PMN stimulation by S proteins induced the release of different chemokines, growth factors, regulatory and proinflammatory cytokines. Overall, our findings show that the SARS-CoV-2 S protein, an anti-spike IgG1 antibody or their immune complex, promote oxidative responses of PMNs in a variant-dependent manner, contributing to a better understanding of the role of PMN responses during SARS-CoV-2 infection., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Almeida, Fantone, Sarr, Ashtiwi, Channell, Grenfell, Martins-Filho and Rada.)

Background: Chronic kidney disease (CKD) is a risk factor for severe coronavirus disease (COVID-19). In Brazil, the disease is the 10th highest cause of death. We evaluated the epidemiological impact of COVID-19 in CDK and non-CDK patients., Methods: Positive patients for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from 2020 to 2022 were classified according to the severity of COVID-19 and the numbers of cases and deaths were correlated to each wave of SARS-CoV-2 variants in Brazil., Results: We compared all variables, and our data show that CDK significantly increased the mortality rate among patients, especially before COVID-19 vaccination, in comparison with non-CKD patients., Conclusions: CKD patients had a significantly increased mortality rate compared with non-CKD., (© The Author(s) 2023. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.)

Since pandemic declaration, the vulnerability of countries with serious economic challenges and limited health resources became evident. This vulnerability has been put to the test once again with the appearance of Omicron as another variant of concern. Although great efforts have been made to develop effective and safe vaccines, they need to be made available globally at an affordable price to all governments and distributed equitably to maximize immediate and long-term efforts to contain the virus and advance global public health. Potential sources of unfair allocation of COVID-19 vaccines are not hard to find. The COVID-19 Vaccine Global Access Facility (COVAX) has so far shipped over 406 million COVID-19 vaccines to 144 eligible participants. From that batches, about 115 million doses (28%) were allocated to 49 African countries. If proactive measures are not undertaken, Nigeria, pointed here as a case study, and Sub-Saharan Africa countries may not be self-reliant for COVID-19 vaccines. This report raises a discussion on the difficulties in accessing vaccines and diagnostics in sub-Saharan Africa, compared to high- and middle-income countries. Now more than ever, it is crucial to note that there is no overcoming a pandemic without coordinated action for actions that go beyond borders. The coordinated effort to raise vaccination rates in the African continent is not a humanitarian action aimed exclusively at Africa, but more than that, it is an effort for the benefit of global public health.

Background: A growing number of long COVID cases after infection have been reported. By definition, long COVID is the condition whereby affected individuals do not recover for several weeks or months following the onset of symptoms suggestive of COVID-19, the profile and timeline of which remains uncertain., Methods: In this work, in-home, outpatient and hospitalized COVID-19 positive patients were monitored for up to 14 mo to establish the prevalence of long COVID symptoms and their correlation with age, pre-existing comorbidities and course of acute infection. The longitudinal study included 646 positive patients who were monitored once a month., Results: From the whole population, 50.2% presented with long COVID syndrome. Twenty-three different symptoms were reported. Most frequent were fatigue (35.6%), persistent cough (34.0%), dyspnea (26.5%), loss of smell/taste (20.1%) and frequent headaches (17.3%). Mental disorders (20.7%), change in blood pressure (7.4%) and thrombosis (6.2%) were also reported. Most patients presented with 2-3 symptoms at the same time. Long COVID started after mild, moderate and severe infection in 60, 13 and 27% of cases, respectively, and it was not restricted to specific age groups., Conclusions: Older patients tended to have more severe symptoms, leading to a longer post-COVID-19 period. The presence of seven comorbidities was correlated with the severity of infection, and severity itself was the main factor that determined the duration of symptoms in long COVID cases., (© The Author(s) 2022. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.)

Background: Effective and safe vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are critical to controlling the COVID-19 pandemic and will remain the most important tool in limiting the spread of the virus long after the pandemic is over., Methods: We bring pioneering contributions on the maintenance of the immune response over a year on a real-life basis study in 1,587 individuals (18-90 yrs, median 39 yrs; 1,208 female/379 male) who underwent vaccination with two doses of CoronaVac and BNT162b2 booster after 6-months of primary protocol., Findings: Elevated levels of anti-spike IgG antibodies were detected after CoronaVac vaccination, which significantly decreased after 80 days and remained stable until the introduction of the booster dose. Heterologous booster restored antibody titers up to-1·7-fold, changing overall seropositivity to 96%. Titers of neutralising antibodies to the Omicron variant were lower in all timepoints than those against Delta variant. Individuals presenting neutralising antibodies against Omicron also presented the highest titers against Delta and anti-Spike IgG. Cellular immune response measurement pointed out a mixed immune profile with a robust release of chemokines, cytokines, and growth factors on the first month after CoronaVac vaccination followed by a gradual reduction over time and no increase after the booster dose. A stronger interaction between those mediators was noted over time. Prior exposure to the virus leaded to a more robust cellular immune response and a rise in antibody levels 60 days post CoronaVac than in individuals with no previous COVID-19. Both vaccines were safe and well tolerated among individuals., Interpretation: Our data approach the effectiveness of CoronaVac association with BNT162b2 from the clinical and biological perspectives, aspects that have important implications for informing decisions about vaccine boosters., Funding: Fiocruz, Brazil., Competing Interests: MN has received research grants from Instituto Butantan, Janssen Vaccines and Prevention B.V., Medicago R&D Inc, and Pfizer/BioNTech SE. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Grenfell, Almeida, Filgueiras, Corsini, Gomes, de Miranda, Lourenço, Martins-Filho, de Oliveira, Teixeira-Carvalho, Campos, Nogueira, Alves, Fernandes, Castilho, Lima, de Abreu, Alvim, Silva, Jeremias, Otta, Campi-Azevedo and Immunita-001 Team.)