SARS-CoV-2 Spike Protein and Neutralizing Anti-Spike Protein Antibodies Modulate Blood Platelet Function.

Several studies report elevated blood platelet activation and altered platelet count in COVID-19 patients, but the role of the SARS-CoV-2 spike protein in this process remains intriguing. Additionally, there is no data that anti-SARS-CoV-2 neutralizing antibodies (nAb) may attenuate spike protein activity toward blood platelets. Our results indicate that under in vitro conditions, the spike protein increased the collagen-stimulated aggregation of isolated platelets and induced the binding of vWF to platelets in ristocetin-treated blood. The spike protein also significantly reduced collagen- or ADP-induced aggregation or decreased GPIIbIIIa (fibrinogen receptor) activation in whole blood, depending on the presence of the anti-spike protein nAb. Our findings suggest that studies on platelet activation/reactivity in COVID-19 patients or in donors vaccinated with anti-SARS-CoV-2 and/or previously-infected COVID-19 should be supported by measurements of spike protein and IgG anti-spike protein antibody concentrations in blood.

Estimation of anti-SARS-CoV-2 IgG titre among blood donors in Ranchi.

Introduction: Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as novel coronavirus (2019-nCoV). The disease presentation ranges from asymptomatic to severe acute respiratory failure requiring intensive care support. Anti-SARS-CoV-2 IgG antibodies are developed either by natural infection from SARS-CoV-2 or by vaccination against COVID-19. The persistence of IgG antibodies allows identification of the people who have been infected in the past, recovered from illness, and possibly become immune. 7 IgG detection and other serological assays will play an important role in research and surveillance. Aims and Objective: The objective of the study is to assess anti-SARS-CoV-2 IgG titre among blood donors and to assess the decreasing incidence of COVID-19 in the department of blood bank, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand. Materials and Methods: An observational, cross-sectional study was conducted at the department of blood bank, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand over a period of 2 months and 14 days from 06 February 2021 to 20 April 2021 who donated at least one unit of blood. Results: This study recorded a greater number of male donors with B+ blood group. The anti-SARS-CoV-2 titre were mostly young adults between 18 and 31 years of age. Conclusion: Seroprevalence was high in males having blood group B+ between 18 and 32 years of age.

Association of humoral immunity status and thrombodynamics after vaccination with Gam-COVID-Vac and CoviVac.

The ongoing pandemic of coronavirus disease 2019 makes it important to study the immunogenicity, the duration of immune response, and the safety of existing vaccines. Aim. As part of a prospective observational study, to assess associations between levels of anti-Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) S protein IgG antibodies and thrombodynamics parameters in individuals vaccinated with Gam-COVID-Vac and CoviVac vaccines. Material and methods. The study included 137 people who completed the first 3 visits: 30 people received the Gam-COVID-Vac, 107 people -- CoviVac. The study participants underwent venous blood sampling before the introduction of the 1st and 2nd vaccine doses, as well as 42 days after the administration of 1st dose in order to quantify the level of IgG antibodies. At each visit, plasma hemostasis parameters were analyzed using a thrombodynamics test. Results. During the follow-up period, there was a clear increase in the level of anti-SARS-CoV-2 S protein IgG antibodies in both groups. At the same time, this increase over time was significantly greater in Gam-COVID-Vac group. There was no correlation detected between thrombodynamics test results and the levels of anti-SARS-CoV-2 S protein IgG antibodies. Conclusion. The data obtained demonstrate the ability of both vaccines to stimulate the production of anti-SARS-CoV-2 antibodies. However, immune response to Gam-COVID-Vac is much higher. The lack of correlation between thrombodynamics and the level of specific antibodies suggests that vaccination for COVID-19 with Gam-COVIDVac and CoviVac does not cause changes in plasma hemostasis and does not increase the risk of thrombosis. (English) [ FROM AUTHOR] Продолжающаяся пандемия новой коронавирусной инфекции (COVID-19, COronaVIrus Disease 2019) делает крайне актуальным изучение иммуногенности, длительности сохранения иммунного ответа и безопасности имеющихся вакцин. Цель. В рамках проспективного наблюдательного исследования изучить ассоциации между уровнем IgG к S белку коронавиру- са SARS-CoV-2 (Severe Acute Respiratory Syndrome CoronaVirus 2) и параметрами тромбодинамики у лиц, вакцинированных против SARS-CoV-2 вакцинами Гам-КОВИД-Вак и КовиВак. Материал и методы. В исследование включено 137 человек, кото- рые полностью прошли первые 3 визита: 30 человек получили вак- цину Гам-КОВИД-Вак, 107 человек -- КовиВак. У участников иссле- дования проводился забор венозной крови перед введением I-го и II-го компонентов вакцины, а также через 42 дня со дня введения I-го компонента с целью количественного определения уровня IgG к S белку. На каждом из визитов проводился анализ показателей плазменного гемостаза при помощи теста тромбодинамики. Результаты. В течение периода наблюдения отмечалась отчетли- вая динамика нарастания уровня IgG антител (АТ) к S белку в обеих группах. При этом увеличение уровня АТ в динамике было значи- тельно бóльшим в группе лиц, вакцинированных Гам-КОВИД-Вак. По результатам исследования плазменного звена гемостаза кор- реляционной связи между уровнями IgG АТ на каждом визите и па- раметрами тромбодинамики выявлено не было. Заключение. Полученные данные демонстрируют способность обеих вакцин стимулировать выработку АТ к SARS-CoV-2. Однако выраженность иммунного ответа на введение Гам-КОВИД-Вак значительно выше. Отсутствие корреляции между показателями тромбодинамики и уровня специфических АТ говорит о том, что вакцинация против COVID-19 вакцинами Гам-КОВИД-Вак и КовиВак не вызывает изменений плазменного гемостаза и не увеличивает риск тромбообразования. (Russian) [ FROM AUTHOR] Copyright of Cardiovascular Therapy & Prevention is the property of Silicea-Poligraf LLC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Analysis of Clinical Course and Vaccination Influence on Serological Response in COVID-19 Convalescents.

Our goal was to assess the anti-SARS-CoV-2 antibodies presence in COVID-19 convalescents and assess the differences in anti-SARS-CoV-2 antibodies production regarding the disease severity, sex, vaccination, and assess the correlation between anti-SARS-CoV-2 antibodies production and inflammatory parameters. Three hundred twenty-two COVID-19 patients (282 hospitalized and 40 patients with oligosymptomatic COVID-19 isolated at homes) were included in the study. Blood was taken at 4 time points: during hospitalization, 1 month, 3 months, and 6 months. Detection of SARS-CoV-2 antibodies was performed with LIAISON SARS-CoV-2 S1/S2 IgG tests (DiaSorin, Italy). Clinical and laboratory parameters were compared. Significant differences between higher anti-SARS-CoV-2 antibodies titer in symptomatic patients 3 months after infection (III sample) and significantly higher ratio II/I in symptomatic patients were observed. Subgroup analysis based on sex showed differences only in laboratory tests, not in serological. Analysis of the results of serological tests showed significant differences in ratio IV/I and a significant increase in antibodies level after vaccination. The most significant rise was observed between the 3rd and 6th month when the patients received a vaccination. Immunological response after COVID-19 infection lasted over 6 months in all patients, although antibodies titers were significantly higher in patients with a history of severe COVID-19 and vaccinated patients. Immunological response after COVID-19 infection did not depend on sex. There was a significant correlation between anti-SARS-CoV-2 antibodies production and the degree of inflammation in the acute phase of the disease (inflammatory parameters in blood and severity of lung affection in CT). IMPORTANCE The results of our study confirm the knowledge on immune response in the Polish population and add new information regarding correlations with the severity of the disease. The data in the literature concerning the correlation between antibodies response and sex are ambiguous, and we did not observe differences between antibodies production and gender, which also adds new information.

SARS-CoV-2-antibody response in health care workers after vaccination or natural infection in a longitudinal observational study.

BACKGROUND: Following a year of development, several vaccines have been approved to contain the global COVID-19 pandemic. Real world comparative data on immune response following vaccination or natural infection are rare. METHODS: We conducted a longitudinal observational study in employees at a secondary care hospital affected by the COVID-19 pandemic. Comparisons were made about the presence of anti-SARS-CoV-2 immunglobulin G (IgG) antibody ratio after natural infection, or vaccination with one or two doses of BioNTech/Pfizer (BNT162b2), or one dose of AstraZenca (Vaxzevria) vaccine. RESULTS: We found a 100% humoral response rate in participants after 2 doses of BNT162b2 vaccine. The antibody ratio in participants with one dose BNT162b2 and Vaxzevria did not differ significantly to those with previous PCR-confirmed infection, whereas this was significantly lower in comparison to two doses of BioNTech/Pfizer. We could not identify a correlation with previous comorbidities, obesity or age within this study. Smoking showed a negative effect on the antibody response (p = 0.006) CONCLUSION: Our data provide an overview about humoral immune response after natural SARS-CoV-2 infection or following vaccination, and supports the usage of booster vaccinations, especially in patients after a natural SARS-CoV-2 infection.

Correlation of sample-to-cut-off ratio of anti-SARS-CoV-2 IgG antibody chemiluminescent assay with neutralization activity: a prospective multi-centric study in India.

Background and Objectives: There are limited published data on association of results from commercial serological anti-SARS-CoV-2 IgG antibody CLIA (chemiluminescent immunoassay) assays with neutralizing antibodies. This study was undertaken with an objective to correlate sample-to-cut-off (S/Co) ratio of CLIA antibody tests with inhibition activity, which may then serve as a valuable guide for labelling plasma as COVID convalescent plasma (CCP) for therapy and assessing vaccine efficacy. Materials and Methods: A total of 139 donor serum samples who were previously RT-PCR positive and had recovered completely from COVID-19 at least 28 days prior to collection of samples were recruited at three sites. The samples were analysed for S/Co ratio and per cent inhibition activity with VITROS SARS-CoV-2 IgG chemiluminescent assay and GenScript cPass SARS-CoV-2 Surrogate Virus Neutralization Test (sVNT) kit, respectively. Linear regression equation and receiver operating characteristic (ROC) curve were used to check the proposed model of comparing S/Co with per cent inhibition. Results: The results indicate very good correlation between the S/Co ratio of the chemiluminescent IgG assay and the neutralization activity depicted by per cent inhibition on sVNT assay. S/Co ratio of 4·04 (low-titre) and 8·19 (high-titre) correlated with 30% and 68% inhibition, respectively. Conclusion: Chemiluminescent SARS-CoV-2 IgG assay can be used as a semi-quantitative test, with a cut-off of >8·19S/Co ratio for selecting donors for convalescent plasma therapy and assessing efficacy of vaccination.

Symptomatic SARS-CoV-2 Reinfection in a Healthy Healthcare Worker in Italy Confirmed by Whole-Genome Sequencing.

This study describes a case of SARS-CoV-2 reinfection confirmed by whole-genome sequencing in a healthy physician who had been working in a COVID-19 hospital in Italy since the beginning of the pandemic. Nasopharyngeal swabs were obtained from the patient at each presentation as part of routine surveillance. Nucleic acid amplification testing was performed on the two samples to confirm SARS-CoV-2 infection, and serological tests were used to detect SARS-CoV-2 IgG antibodies. Comparative genome analysis with whole-genome sequencing was performed on nasopharyngeal swabs collected during the two episodes of COVID-19. The first COVID-19 episode was in March 2020, and the second was in January 2021. Both SARS-CoV-2 infections presented with mild symptoms, and seroconversion for SARS-CoV-2 IgG was documented. Genomic analysis showed that the viral genome from the first infection belonged to the lineage B.1.1.74, while that from the second infection to the lineage B.1.177. Epidemiological, clinical, serological, and genomic analyses confirmed that the second episode of SARS-CoV-2 infection in the healthcare worker met the qualifications for "best evidence" for reinfection. Further studies are urgently needed to assess the frequency of such a worrisome occurrence, particularly in the light of the recent diffusion of SARS-CoV-2 variants of concern.

Prevalence of SARS-CoV-2 antibodies in pediatric healthcare workers.

OBJECTIVES: To determine SARS-CoV-2-antibody prevalence in pediatric healthcare workers (pHCWs). DESIGN: Baseline prevalence of anti-SARS-CoV-2-IgG was assessed in a prospective cohort study from a large pediatric healthcare facility. Prior SARS-CoV-2 testing history, potential risk factors and anxiety level about COVID-19 were determined. Prevalence difference between emergency department (ED)-based and non-ED-pHCWs was modeled controlling for those covariates. Chi-square test-for-trend was used to examine prevalence by month of enrollment. RESULTS: Most of 642 pHCWs enrolled were 31-40years, female and had no comorbidities. Half had children in their home, 49% had traveled, 42% reported an illness since January, 31% had a known COVID-19 exposure, and 8% had SARS-CoV-2 PCR testing. High COVID-19 pandemic anxiety was reported by 71%. Anti-SARS-CoV-2-IgG prevalence was 4.1%; 8.4% among ED versus 2.0% among non-ED pHCWs (p < 0.001). ED-work location and known COVID-19 exposure were independent risk factors. 31% of antibody-positive pHCWs reported no symptoms. Prevalence significantly (p < 0.001) increased from 3.0% in April-June to 12.7% in July-August. CONCLUSIONS: Anti-SARS-CoV-2-IgG prevalence was low in pHCWs but increased rapidly over time. Both working in the ED and exposure to a COVID-19-positive contact were associated with antibody-seropositivity. Ongoing universal PPE utilization is essential. These data may guide vaccination policies to protect front-line workers.

Prospective Sero-epidemiological Evaluation of SARS-CoV-2 among Health Care Workers in a German Secondary Care Hospital.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the pulmonary disease coronavirus disease 2019 (COVID-19, which has challenged health care facilities worldwide. The sustainability of health care systems is largely reliant on the health status of their health care workers (HCW). This study aimed to detect the SARS-CoV-2 virus and specific antibodies among HCWs in a German hospital as a model system for the potential spread of the pandemic. METHODS: Between March and June 2020, we used a combination of RT-PCR testing to detect SARS-CoV-2 RNA and an enzyme-linked immunosorbent assay to detect the presence of anti-SARS-CoV-2 immunoglobulin G (IgG) antibodies among HCWs in a German hospital based on repetitive oropharyngeal swabs (OPSs) and blood samples. RESULTS: In total, 871/1081 employees participated in this prospective longitudinal study. During the study period of 9 weeks, 5329 OPSs and 2136 blood samples were analyzed. SARS-CoV-2 RNA was detected in three participants (0.34%). Anti-SARS-CoV-2 IgG antibodies were detected in 38 (4.36%) participants. CONCLUSION: Our study determined a low prevalence of COVID-19 in HCW, which may reflect the effectiveness of hygiene protocols. However, it could also indicate a low prevalence of SARS CoV-2 in hospital employees. Our study protocol may serve as an instructive example for future pandemic containment protocols in hospitals.