Surveillance of anti-SARS-CoV-2 antibodies in plasma pools and in immunoglobulin medicinal products manufactured since 2020 has shown high neutralizing activity against SARS-CoV-2 and current variants

Background: Patients with primary and secondary immunodeficiencies have shown an impaired humoral immune response to COVID-19 vaccination. It is therefore of paramount importance to investigate anti-SARS-CoV-2 antibody levels in plasma pools and in immunoglobulin (IgG) products used to treat these patients. AIM: To assess the evolution of anti-SARS-CoV-2 antibodies (S protein) in plasma pools and IgG products and its neutralizing activity to original-type virus (Wuhan) and the variants of concern (VOC), including Omicron. Method(s): Healthy donors plasma pools collected in the US and Europe, and the subsequent intravenous (Flebogamma DIFand Gamunex-C, Grifols) and subcutaneous (Xembify, Grifols) IgG manufactured batches were followed from March 2020. Anti-SARS-CoV-2 S protein IgG titers were determined in plasma pools and in IgG batches by ELISA. Neutralization assays analyzed the capacity of IgG products to neutralize original-type virus and VOC (Alpha, Beta, Delta, Omicron BA.1 and BA.5), using pseudo viruses expressing S protein. Results were expressed as the dilution producing 50% neutralization (ID50). Result(s): In plasma pools, anti-SARS-CoV-2 S antibodies continuously increased throughout the study period regardless of the geographic origin. In the US, the first positive plasma pools were collected at the end of 2020. Since July 2021, an exponential increase over 30-fold of anti-SARS-CoV-2 S antibodies was reported. This trend continued increasing until the end of study period. Similarly, IgG products showed a similar evolution of anti-SARS-CoV-2 S antibodies. As expected, IgG batches released at the end of 2020 presented low SARS-CoV-2 neutralization activity. However, IgG products manufactured since August 2021 showed high neutralization activity against original-type virus and the rest of VOC. Regarding Omicron BA.5, a 5 to 10-fold increase was observed over time. Conclusion(s): This study reported the onset of elevated anti-SARS-CoV-2 antibody titers in plasma pools and IgG products since mid-2021, reflecting the evolution of the pandemic and vaccine campaigns. Intravenous and subcutaneous IgG products efficiently neutralized the current circulating VOC, Omicron BA.5. Further research is warranted to assess whether a clinical protective titer against SARS-CoV-2 and passive immunization is achieved in patients with immunodeficiencies treated with IgG products.Copyright © 2023 Elsevier Inc.

Anti-SARS-CoV-2 antibodies important in diagnostics of acute hepatitis in children

The most common causes of acute hepatitis in children are hepatitis A and autoimmune hepatitis. Hepatitis in the course of Wilson's disease is sporadically registered in adolescents. An increase of activity of aminotransferases both in the course of multisystem inflammatory syndrome in children (MIS-C) and in the course of COVID-19 has been observed. Hepatitis is common in children with MIS-C and is associated with a more severe presentation and persistent elevation of liver function tests. To date, no cases of acute hepatitis in children due to COVID-19 have been reported. We present 2 cases of acute hepatitis in children where the only cause seems to be a previous asymptomatic SARS-CoV-2 infection.Copyright © 2023 Termedia Publishing House Ltd.. All rights reserved.

Factors influencing the immune response over 15 months after SARS-CoV-2 infection: A longitudinal population-wide study in the Faroe Islands.

BACKGROUND: The durability of SARS-CoV-2 antibody response and the resulting immunity to COVID-19 is unclear. OBJECTIVES: To investigate long-term humoral immunity to SARS-CoV-2. METHODS: In this nationwide, longitudinal study, we determined antibody response in 411 patients aged 0-93 years from two waves of infections (March to December 2020) contributing 1063 blood samples. Each individual had blood drawn on 4-5 occasions 1-15 months after disease onset. We measured total anti-SARS-CoV-2 receptor-binding domain (RBD) antibody using a qualitative RBD sandwich ELISA, IgM, IgG and IgA levels using an quantitative in-house ELISA-based assay  and neutralizing antibodies (NAbs) using an in-house ELISA-based pseudoneutralizing assay. IgG subclasses were analyzed in a subset of samples by ELISA-based assay. We used nonlinear models to study the durability of SARS-CoV-2 antibody responses and its influence over time. RESULTS: After 15 months, 94% still had detectable circulating antibodies, mainly the IgG isotype, and 92% had detectable NAbs. The distribution of IgG antibodies varied significantly over time, characterized by a biphasic pattern with an initial decline followed by a plateau after approximately 7 months. However, the NAbs remained relatively stable throughout the period. The strength of the antibody response was influenced by smoking and hospitalization, with lower IgG levels in smokers and higher levels in hospitalized individuals. Antibody stability over time was mainly associated with male sex and older age with higher initial levels but more marked decrease. CONCLUSIONS: The humoral immune response to SARS-CoV-2 infection varies depending on behavioral factors and disease severity, and antibody stability over 15 months was associated with sex and age.

Using a multiplex serological assay to estimate time since SARS-CoV-2 infection and past clinical presentation in malagasy patients.

Background: The world is facing a 2019 coronavirus (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this context, efficient serological assays are needed to accurately describe the humoral responses against the virus. These tools could potentially provide temporal and clinical characteristics and are thus paramount in developing-countries lacking sufficient ongoing COVID-19 epidemic descriptions. Methods: We developed and validated a Luminex xMAP® multiplex serological assay targeting specific IgM and IgG antibodies against the SARS-CoV-2 Spike subunit 1 (S1), Spike subunit 2 (S2), Spike Receptor Binding Domain (RBD) and the Nucleocapsid protein (N). Blood samples collected periodically for 12 months from 43 patients diagnosed with COVID-19 in Madagascar were tested for these antibodies. A random forest algorithm was used to build a predictive model of time since infection and symptom presentation. Findings: The performance of the multiplex serological assay was evaluated for the detection of SARS-CoV-2 anti-IgG and anti-IgM antibodies. Both sensitivity and specificity were equal to 100% (89.85-100) for S1, RBD and N (S2 had a lower specificity = 95%) for IgG at day 14 after enrolment. This multiplex assay compared with two commercialized ELISA kits, showed a higher sensitivity. Principal Component Analysis was performed on serologic data to group patients according to time of sample collection and clinical presentations. The random forest algorithm built by this approach predicted symptom presentation and time since infection with an accuracy of 87.1% (95% CI = 70.17-96.37, p-value = 0.0016), and 80% (95% CI = 61.43-92.29, p-value = 0.0001) respectively. Interpretation: This study demonstrates that the statistical model predicts time since infection and previous symptom presentation using IgM and IgG response to SARS-CoV2. This tool may be useful for global surveillance, discriminating recent- and past- SARS-CoV-2 infection, and assessing disease severity. Fundings: This study was funded by the French Ministry for Europe and Foreign Affairs through the REPAIR COVID-19-Africa project coordinated by the Pasteur International Network association. WANTAI reagents were provided by WHO AFRO as part of a Sero-epidemiological "Unity" Study Grant/Award Number: 2020/1,019,828-0 P·O 202546047 and Initiative 5% grant n°AP-5PC-2018-03-RO.

A higher number of SARS-COV-2 infections in quilombola communities than in the local population in Brazil.

The historical and social vulnerability of quilombola communities in Brazil can make them especially fragile in the face of COVID-19, considering that several individuals have precarious health systems and inadequate access to water. This work aimed to characterize the frequency of SARS-COV-2 infections and the presence of IgM and IgG SARS-CoV-2 antibodies in quilombola populations and their relationship with the presence of risk factors or preexisting chronic diseases in the quilombola communities. We analyzed the sociodemographic and clinical characteristics, serological status, comorbidities, and symptoms of 1,994 individuals (478 males and 1,536 females) from 18 Brazilian municipalities in the State of Sergipe of quilombola communities, which were evaluated at different epidemiological weeks, starting at the 32nd (August 6th) and ending at the 40th (October 3rd) epidemiological week. More than 70% of studied families live in rural areas and they have an extreme poverty social status. Although we found a higher number of SARS-COV-2 infections in quilombola communities than in the local population, their SARS-CoV-2 reactivity and IgM and IgG positivity varied across the communities investigated. Arterial hypertension was the most risk factor, being found in 27.8% of the individuals (9.5% in stage 1, 10.8% in stage 2, and 7.5% in stage 3). The most common COVID-19 symptoms and comorbidities were headache, runny nose, flu, and dyslipidemia. However, most individuals were asymptomatic (79.9%). Our data indicate that mass testing must be incorporated into public policy to improve the health care system available to quilombola populations during a future pandemic or epidemic.

The Immune Response to SARS-CoV-2 Vaccine in a Cohort of Family Pediatricians from Southern Italy.

In Italy, from January 2021, the Ministry of Health indicated a vaccination plan against COVID for frail patients and physicians based on a three-dose scheme. However, conflicting results have been reported on which biomarkers permit immunization assessment. We used several laboratory approaches (i.e., antibodies serum levels, flow cytometry analysis, and cytokines release by stimulated cells) to investigate the immune response in a cohort of 53 family pediatricians (FPs) at different times after the vaccine. We observed that the BNT162b2-mRNA vaccine induced a significant increase of specific antibodies after the third (booster) dose; however, the antibody titer was not predictive of the risk of developing the infection in the six months following the booster dose. The antigen stimulation of PBMC cells from subjects vaccinated with the third booster jab induced the increase of the activated T cells (i.e., CD4+ CD154+); the frequency of CD4+ CD154+ TNF-α+ cells, as well as the TNF-α secretion, was not modified, while we observed a trend of increase of IFN-γ secretion. Interestingly, the level of CD8+ IFN-γ+ (independently from antibody titer) was significantly increased after the third dose and predicts the risk of developing the infection in the six months following the booster jab. Such results may impact also other virus vaccinations.

SARS-CoV-2 Positive Serology and Islet Autoantibodies in Newly Diagnosed Pediatric Cases of Type 1 Diabetes Mellitus: A Single-Center Cohort Study.

Acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, although presenting less severe forms of the disease in children, seems to play a role in the development of other conditions, including type 1 diabetes mellitus (T1DM). After the beginning of the pandemic, an increase in the number of T1DM pediatric patients was observed in several countries, thus leading to many questions about the complex relationship between SARS-CoV-2 infection and T1DM. Our study aimed to highlight possible correlations between SARS-CoV-2 serology and T1DM onset. Therefore, we performed an observational retrospective cohort study that included 158 children diagnosed with T1DM in the period April 2021-April 2022. The presence or absence of SARS-CoV-2 and T1DM-specific antibodies and other laboratory findings were assessed. In the group of patients with positive SARS-CoV-2 serology, a higher percentage had detectable IA-2A antibodies, more children were positive for all three islet autoantibodies determined (GADA, ICA, and IA-2A), and a higher mean HbA1c value was found. No difference existed between the two groups regarding DKA presence and severity. A lower C-peptide level was found in the patients presenting diabetic ketoacidosis (DKA) at T1DM onset. When compared to a group of patients diagnosed before the pandemic, an increased incidence of both DKA and severe DKA, as well as a higher age at diagnosis and higher levels of HbA1c were present in our study group. These findings have important implications for the ongoing monitoring and management of children with T1DM after the COVID-19 pandemic and highlight the need for further research to better understand the complex relationship between SARS-CoV-2 infection and T1DM.

The Kinetics of Anti-SARS-CoV-2 Antibodies in Pediatric Patients and the Characterization of Post-COVID-19 Condition at 6 Months After Infection: Protocol for a Longitudinal Observational Study.

BACKGROUND: Data regarding the kinetics of anti-SARS-CoV-2 antibodies and information about post-COVID-19 condition (colloquially known as "long COVID") in children are scarce, especially in low-income countries. Even though cases of COVID-19 in children are less prevalent than adults, post-COVID-19 condition cases in children are high and have a burden that may impact their growth and development. There are other features of antibody kinetics in connection with SARS-CoV-2 infection that are yet unknown as of this writing, especially in children following infection. Furthermore, the long-term results, risk factors, and underlying pathophysiology are still uncertain. To better understand post-COVID-19 condition in children, it is necessary to further investigate the impact of clinically significant factors such multisystem inflammatory syndrome and disease severity among hospitalized survivors through their SARS-CoV-2 antibody response. OBJECTIVE: We aim to analyze anti-receptor-binding domain SARS-CoV-2 immunoglobulin G antibodies over time and characterize the signs and symptoms of post-COVID-19 condition in pediatric patients at the time of diagnosis and at 2 weeks and 1, 3, and 6 months following infection. METHODS: This is a longitudinal observational study in Indonesia. Pediatric patients diagnosed with COVID-19 by positive molecular assay using nasopharyngeal swab will be tested for anti-SARS-CoV-2 antibodies using the Roche Elecsys Anti-SARS-CoV-2 S assay at the time of diagnosis and at 2 weeks and 1, 3, and 6 months following infection. Antibody titer data will be reported as means and SDs. The respondents' signs and symptoms will be observed up to 6 months after the onset of infection, including the vaccination event, reinfection, rehospitalization, and mortality. The clinical features will be reported as frequencies and percentages. RESULTS: Participant enrollment began in February 2022. As of September 30, 2022, a total of 58 patients were enrolled. After data collection, results are expected to be analyzed in August 2023. CONCLUSIONS: This study will allow us to know the kinetics of anti-receptor-binding domain SARS-CoV-2 immunoglobulin G antibodies and data regarding post-COVID-19 condition up to 6 months following infection in the Indonesian pediatric population. Furthermore, this study has the potential to serve as a foundation for government decisions about vaccination programs and prevention measures. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/43344.

Risk factors and characteristics influencing humoral response to COVID-19 vaccination in patients after allogeneic stem cell transplantation.

Introduction: Vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is approved and recommended for immunocompromised patients such as patients after allogeneic stem cell transplantation (allo-SCT). Since infections represent a relevant cause of transplant related mortality we analyzed the advent of immunization to SARS-CoV-2 vaccination in a bicentric population of allogeneic transplanted patients. Methods: We retrospectively analyzed data of allo-SCT recipients in two German transplantation centers for safety and serologic response after two and three SARS-CoV-2 vaccinations. Patients received mRNA vaccines or vector-based vaccines. All patients were monitored for antibodies against SARS-CoV2-spike protein (anti-S-IgG) with an IgG ELISA assay or an EIA Assay after two and three doses of vaccination. Results: A total of 243 allo-SCT patients underwent SARS-CoV-2 vaccination. The median age was 59 years (range 22-81). While 85% of patients received two doses of mRNA vaccines, 10% had vector-based vaccines and 5% received a mixed vaccination. The two vaccine doses were well tolerated with only 3% patients developing a reactivation of graft versus host disease (GvHD). Overall, 72% of patients showed a humoral response after two vaccinations. In the multivariate analysis age at time of allo-SCT (p=0.0065), ongoing immunosuppressive therapy (p= 0.029) and lack of immune reconstitution (CD4-T-cell counts <200/µl, p< 0.001) were associated with no response. Sex, intensity of conditioning and the use of ATG showed no influence on seroconversion. Finally, 44 out of 69 patients that did not respond after the second dose received a booster and 57% (25/44) showed a seroconversion. Discussion: We showed in our bicentric allo-SCT patient cohort, that a humoral response could be achieve after the regular approved schedule, especially for those patients who underwent immune reconstitution and were free from immunosuppressive drugs. In over 50% of the initial non-responders after 2-dose vaccination, a seroconversion can be achieved by boostering with a third dose.

Rapid Detection of SARS-CoV-2 Antigens and Antibodies Using OFET Biosensors Based on a Soft and Stretchable Semiconducting Polymer.

In the midst of the COVID-19 pandemic, adaptive solutions are needed to allow us to make fast decisions and take effective sanitation measures, e.g., the fast screening of large groups (employees, passengers, pupils, etc.). Although being reliable, most of the existing SARS-CoV-2 detection methods cannot be integrated into garments to be used on demand. Here, we report an organic field-effect transistor (OFET)-based biosensing device detecting of both SARS-CoV-2 antigens and anti-SARS-CoV-2 antibodies in less than 20 min. The biosensor was produced by functionalizing an intrinsically stretchable and semiconducting triblock copolymer (TBC) film either with the anti-S1 protein antibodies (S1 Abs) or receptor-binding domain (RBD) of the S1 protein, targeting CoV-2-specific RBDs and anti-S1 Abs, respectively. The obtained sensing platform is easy to realize due to the straightforward fabrication of the TBC film and the utilization of the reliable physical adsorption technique for the molecular immobilization. The device demonstrates a high sensitivity of about 19%/dec and a limit of detection (LOD) of 0.36 fg/mL for anti-SARS-Cov-2 antibodies and, at the same time, a sensitivity of 32%/dec and a LOD of 76.61 pg/mL for the virus antigen detection. The TBC used as active layer is soft, has a low modulus of 24 MPa, and can be stretched up to 90% with no crack formation of the film. The TBC is compatible with roll-to-roll printing, potentially enabling the fabrication of low-cost wearable or on-skin diagnostic platforms aiming at point-of-care concepts.

No effects of COVID-19 on the development of type 1 diabetes autoimmunity and no evidence of an increased frequency of SARS-CoV-2 antibodies in newly diagnosed type 1 diabetes patients relative to healthy subjects.

AIMS: To evaluate the relationship between SARS-CoV-2 infection and autoimmunity in type 1 diabetes (T1D) and SARS-CoV-2 antibodies frequency at diagnosis of T1D during pandemic. METHODS: The presence of T1D-specific autoimmunity was evaluated in a cohort of 99 children and adolescents without diabetes that contracted SARS-CoV-2 infection. Moreover, the frequency of IgM- and IgG-SARS-CoV-2 antibodies was evaluated in 41 newly diagnosed T1D patients not yet vaccinated against SARS-CoV-2 disease, collected during the pandemic, compared to healthy subjects (CTRL). RESULTS: None of the 99 patients that contracted SARS-CoV-2 infection during the pandemic period was found positive for T1D autoantibodies. The frequency of SARS-CoV-2 antibodies was not significantly different in patients newly diagnosed with T1D (12.2%), compared with CTRL (8.4%). Among SARS-CoV-2 antibody positive T1D patients, 80% were target of diabetes autoantibodies and 60% had another concomitant autoimmune disease. Among the CTRL subjects positive for SARS-CoV-2Abs (n = 10), none was found positive for T1D autoantibodies. CONCLUSIONS: The results of the present study do not confirm, at least in the short term, a role of COVID-19 as a potential trigger of T1D autoimmunity and do not provide evidence of an increased frequency of SARS-CoV-2 antibodies in newly diagnosed T1D patients in comparison with healthy population.

Are higher antibody levels against seasonal human coronaviruses associated with a more robust humoral immune response after SARS-CoV-2 vaccination?

The SARS-CoV-2 belongs to the coronavirus family, which also includes common endemic coronaviruses (HCoVs). We hypothesized that immunity to HCoVs would be associated with stronger immunogenicity from SARS-CoV-2 vaccines. The study included samples from the COSRIP observational cohort study of adult paramedics in Canada. Participants provided blood samples, questionnaire data, and results of COVID-19 testing. Samples were tested for anti-spike IgG against SARS-CoV-2, HCoV-229E, HCoV-HKU1, HCoV-NL63, and HCoV-OC43 antigens. We first compared samples from vaccinated and unvaccinated participants, to determine which HCoV antibodies were affected by vaccination. We created scatter plots and performed correlation analysis to estimate the extent of the linear relationship between HCoVs and SARS-CoV-2 anti-spike antibodies. Further, using adjusted log-log multiple regression, we modeled the association between each strain of HCoV and SARS-CoV-2 antibodies. Of 1510 participants (mean age of 39 years), 94 (6.2%) had a history of COVID-19. There were significant differences between vaccinated and unvaccinated participant in anti-spike antibodies to HCoV-HKU1, and HCoV-OC43; however, levels for HCoV-229E and HCoV-NL63 were similar (suggesting that vaccination did not affect these baseline values). Among vaccinated individuals without prior COVID-19 infection, SARS-COV-2 anti-spike IgG demonstrated a weak positive relationship between both HCoV-229E (r = 0.11) and HCoV-NL63 (r = 0.12). From the adjusted log-log multiple regression model, higher HCoV-229E and HCoV-NL63 anti-spike IgG antibodies were associated with increased SARS-COV-2 anti-spike IgG antibodies. Vaccination appears to result in measurable increases in HCoV-HKU1, and HCoV-OC43 IgG levels. Anti-HCoV-229E and HCoV-NL63 antibodies were unaffected by vaccination, and higher levels were associated with significantly higher COVID-19 vaccine-induced SARS-COV-2 antibodies.

Synergistically functionalized molybdenum disulfide-reduced graphene oxide nanohybrid based ultrasensitive electrochemical immunosensor for real sample analysis of COVID-19.

Herein, we have proposed a straightforward and label-free electrochemical immunosensing strategy supported on a glassy carbon electrode (GCE) modified with a biocompatible and conducting biopolymer functionalized molybdenum disulfide-reduced graphene oxide (CS-MoS2/rGO) nanohybrid to investigate the SARS-CoV-2 virus. CS-MoS2/rGO nanohybrid-based immunosensor employs recombinant SARS-CoV-2 Spike RBD protein (rSP) that specifically identifies antibodies against the SARS-CoV-2 virus via differential pulse voltammetry (DPV). The antigen-antibody interaction diminishes the current responses of the immunosensor. The obtained results indicate that the fabricated immunosensor is extraordinarily capable of highly sensitive and specific detection of the corresponding SARS-CoV-2 antibodies with a LOD of 2.38 zg mL-1 in phosphate buffer saline (PBS) samples over a broad linear range between 10 zg mL-1-100 ng mL-1. In addition, the proposed immunosensor can detect attomolar concentrations in spiked human serum samples. The performance of this immunosensor is assessed using actual serum samples from COVID-19-infected patients. The proposed immunosensor can accurately and substantially differentiate between (+) positive and (-) negative samples. As a result, the nanohybrid can provide insight into the conception of Point-of-Care Testing (POCT) platforms for cutting-edge infectious disease diagnostic methods.

Association between serologically confirmed COVID-19 infection and cognitive functioning in community dwelling older adults.

Introduction: COVID-19 infection can impact the central nervous system, and is often associated with cognitive decline. However, there are no studies linking serologically confirmed COVID-19 infection with objectively assessed cognitive functioning. We explored whether presence of SARS-CoV-2 antibodies account for variability in participants' scores on a neuropsychological assessment. Methods: In this cross-sectional study participants were 657 (mean age = 72.97; SD = 6.07 years; women = 47.7%) individuals randomly selected from the general population of the canton of Zurich and included in the Corona Immunitas study. We conducted serological tests between October 2020 and May 2021 to detect and quantify SARS-CoV-2 antibodies in peripheral venous blood samples. We assessed cognitive function, vaccination status (vaccinated; not vaccinated), number of health conditions, and demographic variables between January and August 2021. We studied the association between seropositivity and global cognitive function and five cognitive domains (language expression, language comprehension, temporal orientation, spatial orientation, and memory) with linear regression models. Based on SARS-CoV-2 antibodies and vaccination status, we stratified participants into three groups: No SARS-CoV-2 antibodies (N = 402); SARS-CoV-2 antibodies due to vaccination (N = 218); history of SARS-CoV-2 infection and no vaccination (N = 37). Results: In the regression model adjusted for age, sex, educational level, and number of health conditions, compared to those without SARS-CoV-2 antibodies, those with SARS-CoV-2 antibodies due to vaccination had better global cognitive functioning (Standardized beta = 0.10; 95% CI = 0.02; 0.17), and those with SARS-CoV-2 antibodies due to infection had poorer cognitive functioning (Standardized beta = -0.10; 95% CI = -0.18; -0.03). Regarding cognitive domains, compared to those without SARS-CoV-2 antibodies, those with SARS-CoV-2 antibodies due to infection scored more poorly on language comprehension and temporal orientation, and those with SARS-CoV-2 antibodies due to vaccination scored better on memory. Discussion: By linking serologically confirmed presence of SARS-CoV-2 antibodies to poorer global cognitive functioning in community dwelling older adults we strengthen existing evidence in support of cognitive decline related to COVID-19. Given the large number of infected older adults, and the endurance of the pandemic, our results highlight the need to address COVID-19 related cognitive decline in the clinical and public health areas of prevention, diagnosis, and treatment.

SARS-CoV-2 Detection and COVID-19 Diagnosis: A Bird's Eye View.

The battle against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) associated coronavirus disease 2019 (COVID-19) is continued worldwide by administering firsttime emergency authorized novel mRNA-based and conventional vector-antigen-based antiCOVID-19 vaccines to prevent further transmission of the virus as well as to reduce the severe respiratory complications of the infection in infected individuals. However; the emergence of numerous SARS-CoV-2 variants is of concern, and the identification of certain breakthrough and reinfection cases in vaccinated individuals as well as new cases soaring in some low-to-middle income countries (LMICs) and even in some resource-replete nations have raised concerns that only vaccine jabs would not be sufficient to control and vanquishing the pandemic. Lack of screening for asymptomatic COVID-19-infected subjects and inefficient management of diagnosed COVID-19 infections also pose some concerns and the need to fill the gaps among policies and strategies to reduce the pandemic in hospitals, healthcare services, and the general community. For this purpose, the development and deployment of rapid screening and diagnostic procedures are prerequisites in premises with high infection rates as well as to screen mass unaffected COVID-19 populations. Novel methods of variant identification and genome surveillance studies would be an asset to minimize virus transmission and infection severity. The proposition of this pragmatic review explores current paradigms for the screening of SARS-CoV-2 variants, identification, and diagnosis of COVID-19 infection, and insights into the late-stage development of new methods to better understand virus super spread variants and genome surveillance studies to predict pandemic trajectories.

Dried blood spot eluates are suitable for testing of SARS-CoV-2 IgG antibodies targeting Spike protein 1 and Nucleocapsid protein.

Dried blood spots (DBS) provide easy handling and are thus a beneficial tool for data collection, e.g. for epidemiological studies. The suitability of DBS for the assessment of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was analyzed with regards to the use in future studies addressing seroprevalence in the population. 121 volunteers gave a venous blood sample and capillary blood samples on two DBS cards (PerkinElmer and Ahlstrom-Munksjö) via self-sampling under supervision. All samples were analyzed using the Anti-SARS-CoV-2 ELISA (IgG) and the Anti-SARS-CoV-2 NCP ELISA (IgG) from EUROIMMUN performed on the EUROIMMUN EUROLabWorkstation ELISA. Correlation coefficients between ELISA results based on the different sampling methods were calculated. Results of DBS analysis for SARS-CoV-2 IgG S1 and NCP highly correlated with the serum values (r = 0.96). In addition, the calculation of the phi coefficient showed no significant difference between the qualitative results of both sampling methods (rφ = 0.98-1.0). Further analysis of DBS eluates after prolonged storage of 6-8 h also showed a high correlation with serum results (r = 0.97 and r = 0.93, respectively). The study results indicate suitability of DBS for the analysis of antibodies against SARS-CoV-2 S1 and NCP. For DBS eluate, a stability of 6-8 h for measurement of SARS-CoV-2 antibodies can be assumed.

Better Anti-Spike IgG Antibody Response to SARS-CoV-2 Vaccine in Patients on Haemodiafiltration than on Haemodialysis.

INTRODUCTION: The antibody response to SARS-CoV-2 vaccine in haemodialysis (HD) patients is diminished compared to healthy subjects. The aim of this study was to compare the presence of reactive SARS-CoV-2 antibodies in patients with high-flux HD and on-line haemodiafiltration (HDF) three and 6 months after the second dose of SARS-CoV-2 vaccine since previous studies indicate that a sustained antibody response correlates with protection from disease. METHODS: We included 216 HD patients of which 157 had on-line HDF and 59 high-flux HD and 46 health care workers as controls and studied the presence of reactive anti-spike IgG antibodies three and 6 months after the second dose of SARS-CoV-2 vaccine. Clinical features between the patient groups were similar, but patients with on-line HDF had significantly higher Kt/V. RESULTS: The percentage of participants with reactive antibodies was significantly lower in patients compared to controls, both three and 6 months after the second dose of vaccine. Furthermore, the proportion of patients with reactive anti-spike IgG ≥1.0 6 months after the second dose of vaccine was significantly higher in patients with on-line HDF compared to in patients with high-flux HD. In logistic regression analyses adjusted for several clinical features, the variables associated with presence of reactive anti-spike IgG at 3 months after the second dose of vaccine were lower age, HDF treatment, not being obese and not having a previous solid organ transplant. The two variables with the strongest influence on the presence of reactive anti-spike IgG levels 6 months after the second dose of vaccine were treatment with on-line HDF and not having immunosuppressive therapy. CONCLUSION: This is the first study to show that on-line HDF preserves the antibody response better than high-flux HD after vaccination with SARS-CoV-2 vaccine. Treatment strategies that sustain the vaccine response are essential to apply in this vulnerable group of patients.

A Microfluidic Biosensor for Rapid Detection of Covid-19

We have designed, fabricated, and tested a MEMS-based impedance biosensor for accurate and rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) using of clinical samples. The device consists of focusing region that concentrate low quantities of the virus present in the samples to a detectable threshold, trap region hat maximize the captured virus, and detection region to detect the virus with high selectivity and sensitivity, using an array of interdigitated electrodes (IDE) coated with a specific antibody. Changes in the impedance value due to the binding of the SARS-COV-2 antigen to the antibody will indicate positive or negative result. The device was able to detect inactivated SARS-COV-2 antigen present in phosphate buffer saline (PBS) with a concentration as low as 50 TCID50/ml in 30 minutes. In addition, the biosensor was able to detect SARS-COV-2 in clinical samples (swabs) with a sensitivity of 84 TCID50/ml, also in 30 minutes. © 2023 IEEE.

Seroprevalence of SARS-CoV2 Antibodies among Patients and Healthy Individuals of Lahore

Objective: To determine the seroprevalence of SARS-CoV2 antibodies in patients and healthy individuals presenting to a tertiary care hospital in Lahore. Study Design: Cross-sectional study Place and Duration of Study: Pathology Department of Surayya Azeem Hospital, Lahore Pakistan, from May to Jul 2020. Methodology: The study included clinically suspected patients of COVID-19 referred by clinicians and healthy individuals presenting to the hospital for the SARS-CoV-2 antibody test, irrespective of age and gender. Results: The SARS-CoV-2 antibody positivity was 704(59.4%) in our study. Out of 1184 individuals tested, 690 patients had a positive clinical history of COVID-19 infection, and 517(74.9%) were positive for COVID-19 antibodies. Out of 494 asymptomatic healthy individuals, positivity for COVID-19 antibodies was 187(37.8%). It was observed that positivity was significantly higher 169(44.0%) in contacts of COVID-19 infection patients compared to asymptomatic healthy individuals 18(16.3%). Conclusion: Our study shows that the seroprevalence of SARS-CoV-2 antibodies in the general public in Pakistan has greatly increased. © 2023, Army Medical College. All rights reserved.

Selection of a SARS-CoV-2 antibody quantification method and development of an antibody reference standard for ELISA to test immunoglobulin preparations.

The development of COVID-globulin, a COVID-19-specific human immunoglobulin preparation, involved choosing a method to quantify antibodies to SARS-CoV-2. Antibody titre determination by virus neutralisation (VN) is labour-intensive and unsuitable for large-scale application. To enable routine testing, it was necessary to develop a less demanding method;the enzyme-linked immunosorbent assay (ELISA) was the most appropriate of solutions. The lack of international and industry reference standards (RS) prompted the preparation and certification of an RS for COVID-globulin potency control. The aim of the study was to examine the possibility of substituting ELISA for VN and to develop an RS for SARS-CoV-2 antibody quantification in immunoglobulin preparations. Material(s) and Method(s): the authors used commercial ELISA kits by several manufacturers, COVID-globulin by Microgen (48 batches), and human plasma samples from multiple sources (1499 samples). The tests were performed by VN, ELISA, and chemiluminescent microparticle immunoassay. Result(s): the authors validated an ELISA method for SARSCoV-2 antibody quantification with the selected reagent kits by the National Medical Research Center for Hematology (NMRC for Hematology) and Euroimmun AG. The authors demonstrated the possibility of using ELISA instead of VN (with a correlation coefficient of more than 0.9). They developed and characterised an in-house RS for SARS-CoV-2 antibody content in human immunoglobulin preparations. The RS was certified in newly introduced anti-COVID units (ACU) and in international binding antibody units (BAU) using the World Health Organisation (WHO) international reference panel (NIBSC code: 20/268). The RS's potency was measured in terms of its neutralising activity in ACU (320 ACU/mL) and BAU (2234.8 BAU/mL). The authors established the relationship between ACU and BAU units. For the selected ELISA reagent kits, the conversion factors were 6.4 (NMRC for Hematology) and 7.0 (Euroimmun AG). Conclusion(s): the ELISA method for SARS-CoV-2 antibody quantification and the RS for SARS-CoV-2 antibody content can be applied to determine the potency of human anti-COVID-19 immunoglobulins.Copyright © 2023 Safety and Risk of Pharmacotherapy. All rights reserved.