Frequency of SARS-CoV-2 infection in hemodialysis patients

Patients with end-stage chronic kidney disease treated with hemodialysis are at risk of infection and severe course of the new coronavirus infection. This opinion was based on the data obtained as a result of PCR testing during the active phase of the disease with detailed clinical symptoms. However, this diagnostic method does not allow one to fully assess the prevalence of infection in the population. The aim - studying of the frequency of SARS-CoV-2 infection in patients receiving hemodialysis treatment and the spectrum of antiviral antibodies, depending on the nature of the course of COVID-19. Material and methods. 100 patients with chronic kidney disease (stage 5D) treated at the outpatient Dialysis Center (MCVTP) were included in the study by a simple random sample. The assessment of SARS-CoV-2 infection was carried out by analyzing the material of smears obtained from the naso-oropharynx by PCR and blood serum samples by ELISA. The study excluded 14 patients with dubious results for the determination of serological markers SARS-CoV-2 and 1 patient with active infection, who was isolated from the RNA of the virus. Results. IgM and IgG antibodies were detected in 49 (57.6%) of the 85 examined patients. 24 of them (group 1) were diagnosed with COVID-19 infection with typical clinical symptoms 3-9 months ago, and 25 (group 2) had no clinical manifestations of the acute respiratory infection at the appropriate time suggesting an asymptomatic course of the disease. IgM class antibodies were detected with equal frequency in group 1 and in group 2 (33.3 vs 24.0%, respectively, p<0.6). IgG antibodies exclusively to the nucleocapsid N-protein (IgGn) were detected only in the latent form of the disease (32%), while antibodies against the S-protein (spike protein) of the virus (IgGs and IgGn+s) were detected more often in the manifest form compared to the asymptomatic one (100 vs 60%, respectively, p<0.05). Conclusion. In a random cohort of patient receiving hemodialysis treatment, more than half were asymptomatic.Despite a wide range of prevention measures, SARS-CoV-2 infection among patients treated with hemodialysis is more than 2 times higher than in the general population.Copyright © 2021 Geotar Media Publishing Group. All rights reserved.

DYNAMICS IN MATURATION OF SARS-CoV-2 RBD-SPECIFIC IgG ANTIBODY AVIDITY DEPENDING ON IMMUNIZATION TIMEFRAME AND TYPE.

The aim is to examine dynamics of avidity maturation of IgG antibodies against SARS-CoV-2 RBD depending on the type of immunization (vaccination or infection), as well as on the duration and frequency of immunization. Materials and methods. The study was performed on two sample cohorts collected at two time points during COVID-19 pandemic. The first cohort (group No. 1) consisted of 87 samples of blood sera obtained from COVID-19 convalescents in the period from March to September 2020. The second cohort included 204 samples obtained in September 2021 from two patient groups. Group No. 2 (n = 64) - patients immunized with a full course of Gam-Covid-Vac, group No. 3 (n = 140) - COVID-19 convalescent patients and subjects vaccinated with Gam-Covid-Vac ("hybrid immunity"). Results and conclusion. The dynamics of avidity maturation for SARS-CoV-2 RBD IgG antibodies depending on the method and frequency of immunization, showed that the most effective immunity was formed in COVID-19 convalescent patients and subjects vaccinated with a full course of Gam-Covid-Vac. The "hybrid" immunity showed not only a significantly higher (compared with groups No. 1 and No. 2) level of IgG antibodies (median 228 BAU/ml vs 75 or 119 BAU/ml, p < 0.001), but also a higher level of avidity (IA 90.5% vs 54.5 and 76.6, respectively, p < 0.001, 4M urea). In the test for assessing the avidity index with the denaturing agent 8M urea in patients with "hybrid immunity", the median level of IA was 25% versus 14.8% and 16% in COVID-19 convalescents and vaccinated subjects (p < 0.001), only in 8 patients IA was higher than 50%. While comparing a single infection of COVID-19 with a full course of Gam-Covid-Vac, it was shown that vaccination leads to higher IgG levels (median values in groups 119 and 75 BAU/ml, p < 0.001) and to a higher avidity index (median 76.6% vs 54.5%). Thus, the more rapid induction of high-avidity antibodies was in vaccinated individuals at early stages of immunization (up to 4 months), during the period when IgG avidity maturation has not yet been completed. Our results showed that during this period vaccination leads to production of antibodies with avidity index at median level of 82% versus 36% in COVID-19 convalescents at similar time point.Copyright © 2023 Saint Petersburg Pasteur Institute. All rights reserved.

Performance of VIDAS® Diagnostic Tests for the Automated Detection of Dengue Virus NS1 Antigen and of Anti-Dengue Virus IgM and IgG Antibodies: A Multicentre, International Study.

Dengue is a serious mosquito-transmitted disease caused by the dengue virus (DENV). Rapid and reliable diagnosis of DENV infection is urgently needed in dengue-endemic regions. We describe here the performance evaluation of the CE-marked VIDAS® dengue immunoassays developed for the automated detection of DENV NS1 antigen and anti-DENV IgM and IgG antibodies. A multicenter concordance study was conducted in 1296 patients from dengue-endemic regions in Asia, Latin America, and Africa. VIDAS® dengue results were compared to those of competitor enzyme-linked immunosorbent assays (ELISA). The VIDAS® dengue assays showed high precision (CV ≤ 10.7%) and limited cross-reactivity (≤15.4%) with other infections. VIDAS® DENGUE NS1 Ag showed high positive and negative percent agreement (92.8% PPA and 91.7% NPA) in acute patients within 0-5 days of symptom onset. VIDAS® Anti-DENGUE IgM and IgG showed a moderate-to-high concordance with ELISA (74.8% to 90.6%) in post-acute and recovery patients. PPA was further improved in combined VIDAS® NS1/IgM (96.4% in 0-5 days acute patients) and IgM/IgG (91.9% in post-acute patients) tests. Altogether, the VIDAS® dengue NS1, IgM, and IgG assays performed well, either alone or in combination, and should be suitable for the accurate diagnosis of DENV infection in dengue-endemic regions.

DYNAMICS IN MATURATION OF SARS-CoV-2 RBD-SPECIFIC IgG ANTIBODY AVIDITY DEPENDING ON IMMUNIZATION TIMEFRAME AND TYPE

The aim is to examine dynamics of avidity maturation of IgG antibodies against SARS-CoV-2 RBD depending on the type of immunization (vaccination or infection), as well as on the duration and frequency of immunization. Materials and methods. The study was performed on two sample cohorts collected at two time points during COVID-19 pandemic. The first cohort (group No. 1) consisted of 87 samples of blood sera obtained from COVID-19 convalescents in the period from March to September 2020. The second cohort included 204 samples obtained in September 2021 from two patient groups. Group No. 2 (n = 64) — patients immunized with a full course of Gam-Covid-Vac, group No. 3 (n = 140) — COVID-19 convalescent patients and subjects vaccinated with Gam-Covid-Vac ("hybrid immunity”). Results and conclusion. The dynamics of avidity maturation for SARS-CoV-2 RBD IgG antibodies depending on the method and frequency of immunization, showed that the most effective immunity was formed in COVID-19 convalescent patients and subjects vaccinated with a full course of Gam-Covid-Vac. The "hybrid” immunity showed not only a significantly higher (compared with groups No. 1 and No. 2) level of IgG antibodies (median 228 BAU/ml vs 75 or 119 BAU/ml, p < 0.001), but also a higher level of avidity (IA 90.5% vs 54.5 and 76.6, respectively, p < 0.001, 4M urea). In the test for assessing the avidity index with the denaturing agent 8M urea in patients with "hybrid immunity”, the median level of IA was 25% versus 14.8% and 16% in COVID-19 convalescents and vaccinated subjects (p < 0.001), only in 8 patients IA was higher than 50%. While comparing a single infection of COVID-19 with a full course of Gam-Covid-Vac, it was shown that vaccination leads to higher IgG levels (median values in groups 119 and 75 BAU/ml, p < 0.001) and to a higher avidity index (median 76.6% vs 54.5%). Thus, the more rapid induction of high-avidity antibodies was in vaccinated individuals at early stages of immunization (up to 4 months), during the period when IgG avidity maturation has not yet been completed. Our results showed that during this period vaccination leads to production of antibodies with avidity index at median level of 82% versus 36% in COVID-19 convalescents at similar time point. © 2023 Saint Petersburg Pasteur Institute. All rights reserved.

Seroprevalence of COVID-19 infection in a rural district of Tamil Nadu: A population-based seroepidemiological study

Background: Coronavirus disease 2019 (COVID-19) was a recent global pandemic of the era which posed a great challenge for the health care in terms of preventive, diagnostic and treatment dimensions. The seroprevalence rate of COVID IgG antibodies is very crucial in estimating the susceptibility of a particular area to the viral disease. In our study, we estimated the seroprevalence of COVID-19 in a rural area. Aims and Objectives: We aimed to estimate the seroprevalence of COVID-19 in a rural district of Tamil Nadu, 6 months after the index case. Materials and Methods: We conducted a cross-sectional study of 509 adults aged more than 18 years. From all the seven Taluks, two gram panchayats (administrative cluster of 8-10 villages) were randomly selected followed by one village through convenience. The participants were invited for the study to the community-based study kiosk set up in all the eight villages through village health committees. We collected sociodemographic characteristics and symptoms using a mobile application-based questionnaire, and we tested samples for the presence of IgG antibodies for severe acute respiratory syndrome coronavirus 2 using an electro chemiluminescent immunoassay. We calculated age-gender adjusted and test performance adjusted seroprevalence. Results: The age-and gender-adjusted seroprevalence was 8.5% (95% confidence interval [CI] 6.9-10.8%). The unadjusted seroprevalence among participants with hypertension and diabetes was 16.3% (95% CI: 9.2-25.8) and 10.7% (95% CI: 5.5-18.3), respectively. When we adjusted for the test performance, the seroprevalence was 6.1% (95% CI 4.02-8.17). The study estimated 7 (95% CI 1:4.5-1:9) undetected infected individuals for every reverse transcription polymerase chain reaction confirmed case. Infection fatality rate (IFR) was calculated as 12.38/10,000 infections as on October 22, 2020. History of self-reported symptoms and education were significantly associated with positive status (P<0.05). Conclusion: A significant proportion of the rural population in a district of Tamil Nadu remains susceptible to COVID-19. A higher proportion of susceptible, relatively higher IFR, and a poor tertiary health-care network stress the importance of sustaining the public health measures and promoting early access to the vaccine are crucial to preserving the health of this population. Low population density, good housing, adequate ventilation, limited urbanization combined with public, private, and local health leadership are critical components of curbing future respiratory pandemics. [ FROM AUTHOR] Copyright of Asian Journal of Medical Sciences is the property of Manipal Colleges of Medical Sciences 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.)

Antibody Response to the SARS-CoV-2 Spike and Nucleocapsid Proteins in Patients with Different COVID-19 Clinical Profiles.

The first case of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in Brazil was diagnosed on February 26, 2020. Due to the important epidemiological impact of COVID-19, the present study aimed to analyze the specificity of IgG antibody responses to the S1, S2 and N proteins of SARS-CoV-2 in different COVID-19 clinical profiles. This study enrolled 136 individuals who were diagnosed with or without COVID-19 based on clinical findings and laboratory results and classified as asymptomatic or as having mild, moderate or severe disease. Data collection was performed through a semistructured questionnaire to obtain demographic information and main clinical manifestations. IgG antibody responses to the S1 and S2 subunits of the spike (S) protein and the nucleocapsid (N) protein were evaluated using an enzyme-linked immunosorbent assay (ELISA) according to the manufacturer's instructions. The results showed that among the participants, 87.5% (119/136) exhibited IgG responses to the S1 subunit and 88.25% (120/136) to N. Conversely, only 14.44% of the subjects (21/136) displayed S2 subunit responses. When analyzing the IgG antibody response while considering the different proteins of the virus, patients with severe disease had significantly higher antibody responses to N and S1 than asymptomatic individuals (p ≤ 0.0001), whereas most of the participants had low antibody titers against the S2 subunit. In addition, individuals with long COVID-19 showed a greater IgG response profile than those with symptomatology of a short duration. Based on the results of this study, it is concluded that levels of IgG antibodies may be related to the clinical evolution of COVID-19, with high levels of IgG antibodies against S1 and N in severe cases and in individuals with long COVID-19.

Studying the efficacy, safety, and immunogenicity of the covishield vaccine in healthcare personnel in an Indian scenario

Background: COVID-19 has largely affected humans with high infection spread and mortality rates globally including India with no specific vaccine or therapy proven effective for its management as the immune response to COVID-19 is not well understood. Covishield has been largely distributed and administered in Indian subjects. However, its efficacy and safety are still unclear raising doubts. Aim: The present study aimed to assess the efficacy, safety, and immunogenicity of the Covishield vaccine in healthcare personnel in India. Methods: In 244 healthcare workers, SARS CoV2 IgG antibodies were assessed before and following the vaccination with two doses of Covishield given at 4 to 6 weeks apart. The efficacy of the vaccine and adverse effects after immunization were evaluated till two months after vaccination. The most common side-effect seen after the 1st dose was pain at the site of injection reported in 53.27% (n=130) study subjects followed by fever in 27.86% (n=68) study subjects, body ache in 22.95% (n=56) study subjects Results: Before vaccination, IgG was positive in 21.31% (n=52) study subjects and was negative in 78.68% (n=192) study subjects. Post-vaccination, IgG-positive status was seen in 69.67% (n=170) study subjects and was not seen in 30.32% (n=74) study subjects. In the infected group having 62 subjects, post-vaccination IgG positive was seen in 96.77% (n=60) study subjects and not seen in 3.22% (n=2) study subjects. In the uninfected group including the 182 subjects, post vaccination IgG positive was seen in 60.43% (n=110) study subjects and was not seen in 39.56% (n=72) study subjects respectively. After 2nd dose, the most common side-effect was pain at the site of injection seen in 24.59% (n=60) study subjects followed by headache in 12.29% (n=30) study subjects, fever in 7.37% (n=18) study subjects, body ache in 3.27% (n=8) participants, low backache and fatigue in 1.63% (n=4) study subjects each and local swelling in 0.81% (n=2) study subjects respectively. All the side effects had a non-significant difference except body ache which was significantly higher after 1st dose with p=0.02. Conclusion: Covishield vaccine has acceptable safety profile levels with increased seropositivity with more intervals in the two doses of the Covishield vaccine. Covishield does not prevent breakthrough infection. However, it can reduce the infection severity of COVID-19.

Maternal COVID-19 Infection: A Cause of Neonatal Stroke?

Perinatal arterial ischemic stroke (PAIS) is a rare cause of neonatal seizures, with an incidence of 1 in 2500 to 4000 live births, globally. This is a case of a neonate with PAIS due to transpla-cental passage of COVID-19 IgG antibodies from the mother. A term, male neonate, born to a primigravida with an unevent-ful antenatal history was presented on the second day of life with multiple episodes of focal clonic seizures involving the right upper and lower limbs. Magnetic resonance imaging revealed an acute infarct in the left frontal lobe, extending into the parietal region, anterior limb, and genu of internal capsule suggestive of arterial ischemic stroke. The known causes of PAIS were evaluated and ruled out. The result of reverse transcription polymerase chain reaction analysis for SARS-CoV-2 antigen was negative for both the mother and the neonate. COVID-19 IgG antibodies in the mother and neonate were elevated. Seizures were controlled with antiepileptics. The neonate had no further seizure episodes and was discharged on oral levetiracetam. The infant was developmentally and neurologically normal at 3 months of age. PAIS is a rare cause of neonatal seizures, and maternal COVID-19 infection may be associated with neonatal stroke.Copyright © 2022, Himalaya Wellness Company. All rights reserved.

SARS-CoV-2-specific antibody responses following BNT162b2 vaccination in individuals with multiple sclerosis receiving different disease-modifying treatments.

Introduction: The study aims to evaluate the concentration of IgG antibodies against the receptor-binding domain of the SARS-CoV-2 spike1 protein (S1RBD) in BNT162b2- vaccinated relapsing-remitting multiple sclerosis (RRMS) individuals receiving disease-modifying treatments (DMTs). Methods: Serum from 126 RRMS volunteers was collected 3 months after the administration of the second dose of the Pfizer-BioNTech BNT162b2 vaccine. Additional samples were analyzed after the administration of the booster dose in fingolimod- treated MS. Anti-S1RBD IgG antibody concentrations were quantified using the ABBOTT SARS-CoV-2 IgG II Quant assay. Results: Anti-S1RBD IgG antibody concentrations in RRMS individuals receiving natalizumab, interferons, teriflunomide, and dimethyl fumarate showed no significant difference to those in healthy controls. However, fingolimod-treated MS individuals showed a marked inability to produce SARS-CoV-2- specific antibodies (p < 0.0001). Furthermore, a booster dose was not able to elicit the production of IgG antibodies in a large portion of matched individuals. Discussion: A possible explanation for the altered immune response in fingolimod- treated MS individuals could be due to the medication inhibiting the circulation of lymphocytes, and possibly in turn inhibiting antibody production. Overall, patients on DMTs are generally of no disadvantage toward mounting an immune response against the vaccine. Nevertheless, further studies require evaluating non-humoral immunity against SARS-CoV-2 following vaccination, as well as the suitability of such vaccinations on patients treated with fingolimod.

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.

Increase in SARS-CoV-2 RBD-Specific IgA and IgG Antibodies in Human Milk From Lactating Women Following the COVID-19 Booster Vaccination.

BACKGROUND: The United States Centers for Disease Control and Prevention recommended a third dose or booster of the Pfizer-BioNTech Comirnaty (BNT162b2) COVID-19 mRNA vaccine in September 2021 for high-risk individuals. Pregnant and high-risk lactating women were encouraged to receive the booster to obtain potential prolonged protection for themselves and their infants. RESEARCH AIM: To investigate the ability of the booster vaccine to increase IgA and IgG antibodies specific to the receptor-binding domain of the SARS-CoV-2 spike protein in human milk compared to levels pre-booster. METHODS: This was a prospective one-group study with a pretest-posttest design. Six of 12 participants were recruited prospectively. Participants were instructed to collect ≥ 2 ounces of milk in the morning at 30 days and 1-day pre-booster, and 7, 14, 21, 30, 45, and 60 days post-booster. Levels of IgA and IgG antibodies specific to the receptor-binding domain of the SARS-CoV-2 spike protein were quantified in human milk via an ELISA assay. RESULTS: We found a significant increase in anti-receptor-binding domain-specific IgA and IgG antibodies in human milk 1-2 weeks after the Pfizer-BioNTech booster and at the study endpoint (45- and 60-days post-booster). CONCLUSIONS: This suggests that the booster vaccination enhances SARS-CoV-2 specific immunity in human milk, which may be protective for infants.

[Survey of spike-specific immunoglobulin G antibodies at approximately 3 months and 9 months after vaccination against coronavirus disease 2019 (severe acute respiratory syndrome coronavirus-2 [SARS-CoV-2]) in health care workers].

OBJECTIVE: We investigated the antibody titer of spike-specific immunoglobulin G (IgG) antibodies after receiving coronavirus repair uridine ribonucleic acid (RNA) vaccine (BNT162b2, Pfizer) in health care workers. METHODS: At one hospital, health care workers received the vaccination between February and May 2021. A survey using questionnaires and spike-specific IgG antibody tests (Abbott) was conducted in 293 participants who had been vaccinated at least once and consented to this study at the time of medical checkups between April and May 2021. We calculated the antibody titer in each age group and days post-vaccination. We examined whether antibody titers of 4,000 AU/mL or higher (probability of high titer: approximately 95%, Abbott) were associated with adverse reactions after vaccination. In addition (1), the antibody titers at approximately 100 days after the second vaccination in 11 participants were remeasured. Furthermore (2), the antibody titers at approximately 260 days after the second vaccination in 13 participants were remeasured and compared with the initial measurements. RESULTS: Of the participants, 276 were post-2 doses (A), 14 were post-1 dose (B), and 3 discontinued the second vaccination (C) at the time of health checkup. The median antibody titer was 11,045.8 AU/mL (50.7-40,000) in group A, 122.7 AU/mL (2.6-1,127.0) in group B, 27,099.3 AU/mL in one of group C who had recovered from coronavirus disease 2019 (COVID-19), and 574.2 AU/mL (283.3 and 865.1) in the other two of group C. The median antibody titer was the highest in those in their 20s, and there was a significant difference between those under and above 40 years of age. The median titer was the highest in 2 weeks to 1 month after the second vaccination. After the second dose, fatigue (≥ moderate) was associated with antibody titers of 4,000 AU/mL or higher. The antibody titers of 11 and 13 participants at approximately 100 and 260 days after the second vaccination were significantly lower than those at the first measurement, with median values of 2,838.0 AU/mL (832.9-5,698.6) and 512.0 AU/mL (154.0-1,220.0), respectively. CONCLUSIONS: Antibody titers were higher in participants under 40 years of age than those 40 years or older. In addition, the percentage of high antibody titer (≧ 4,000 AU/mL) was higher in those who had severe fatigue after the second vaccination. The peak of antibody titer after the second dose was approximately 1 month, and the titer may decline gradually.

Seroprevalence of SARS-CoV-2 antibodies in Italy in newborn dried blood spots.

OBEJCTIVES: Serosurveys can be used to monitor COVID-19 seroprevalence and conduct surveillance. Dried blood spot (DBS), used increasingly as a valuable sample to assay severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibodies (Ab), has several advantages, particularly in infants, due to the limited amount of blood required and its utility in testing a large number of samples in a limited time-frame. We evaluated SARS-CoV-2 IgG Ab prevalence in newborn DBS in the Trentino region of Italy, during the time period January 2020 - December 2021. METHODS: Anti-SARS-CoV-2 IgG levels were determined in DBS by means of Anti-SARS-CoV-2 QuantiVac IgG ELISA assay (Euroimmun, Lubeck, Germany). RESULTS: Analyses included 2,400 DBS from newborns (54% M, 46% F), samples being collected 2-3 days after birth. The first DBS that tested positive for anti-SARS-CoV-2 IgG antibodies was found in March 2020 and, up to May 2020, only 4 positive results were detected overall. Starting from June 2020, the positivity thresholds increased according to the epidemiological waves of the COVID-19 pandemic in Italy, with a robust increment in the winters of 2020 and 2021. The percentage of positive DBS rose from 0 to 6% to 10-47%, in 2020 and 2021, respectively. CONCLUSIONS: This study demonstrates DBS is a suitable tool for both epidemiological purposes and surveillance in the SARS-CoV-2 pandemic, particularly in newborns and pregnant women, saving blood waste and sparing patients any discomfort.

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.

Immunoglobulin G antibody response to the Sputnik V vaccine: previous SARS-CoV-2 seropositive individuals may need just one vaccine dose.

INTRODUCTION: We evaluated the immunoglobulin (Ig) G antibody response against the nucleocapsid protein (NP) and the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 in a cohort of 86 individuals in Venezuela, before and after receiving the Sputnik V vaccine. METHODS: Antibody responses against NP and RBD were determined with an enzyme-linked immunosorbent assay just before, 3 weeks after the first, and 6 weeks after the second dose of the vaccine. RESULTS: Before vaccination, 59 individuals were seronegative, and 27 seropositive for NP and/or RBD. Of the seronegative cohort, 42% did not develop an IgG immune response against RBD after the first vaccine dose, but 100% had a strong IgG response after 2 doses. All seropositive individuals developed a strong IgG antibody response against RBD after the first vaccine dose, with antibody levels ∼40% higher than seronegative individuals who had received 2 doses. Previously seropositive subjects showed no significant increase in IgG antibody response against RBD after the second vaccine dose. CONCLUSIONS: We demonstrate that 2 doses of the Sputnik V vaccine triggered antibody response in all study individuals. The second Sputnik V dose had no impact on IgG response for those seropositive for SARS-CoV-2 antigens before vaccination.

SARS-CoV-2 spike IgG titres up to 137 days following Comirnaty mRNA COVID-19 vaccination, Israel, February to May 2021.

BackgroundData regarding the long-term protection afforded by vaccination for the SARS-CoV-2 infection are essential for allocation of scarce vaccination resources worldwide.MethodsWe conducted a retrospective cohort study aimed at studying the kinetics of IgG antibodies against SARS-CoV-2 in COVID-19-naïve patients fully vaccinated with two doses of Comirnaty mRNA COVID-19 vaccine. Geometric mean concentrations (GMCs) of antibody levels were reported. Linear models were used to assess antibody levels after full vaccination and their decline over time.ResultsThe study included 4,740 patients and 5,719 serological tests. Unadjusted GMCs peaked 28-41 days after the first dose at 10,174 AU/mL (95% CI: 9,211-11,237) and gradually decreased but remained well above the positivity cut-off. After adjusting for baseline characteristics and repeated measurements, the antibodies half-life time was 34.1 days (95% CI: 33.1-35.2), and females aged 16-39 years with no comorbidities had antibody levels of 20,613 AU/mL (95% CI: 18,526-22,934) on day 28 post-first-dose. Antibody levels were lower among males (0.736 of the level measured in females; 95% CI: 0.672-0.806), people aged 40-59 (0.729; 95% CI: 0.649-0.818) and ≥ 60 years (0.452; 95% CI: 0.398-0.513), and patients having haematological (0.241; 95% CI: 0.190-0.306) or solid malignancies (0.757; 95% CI: 0.650-0.881), chronic kidney disease with glomerular filtration rate (GFR) ≥ 30 (0.434; 95% CI: 0.354-0.532) or with GFR < 30 mL/min (0.176; 95% CI: 0.109-0.287), and immunosuppression (0.273; 95% CI: 0.235-0.317). Body mass index, cardiovascular disease, congestive heart failure, chronic obstructive pulmonary disease, diabetes and inflammatory bowel diseases were not associated with antibody levels.ConclusionsVaccination with two doses resulted in persistently high levels of antibodies (≥ cut-off of 50 AU/mL) up to 137 days post-first-dose. Risk factors for lower antibody levels were identified.

Outliers Matter-Correlation between S1 IgG SARS-CoV-2 Antibodies and Neutralizing SARS-CoV-2 Antibodies.

Vaccination against the SARS-CoV-2 virus or infection with SARS-CoV-2 will lead to the development of IgG antibodies against the S1 protein of the SARS-CoV-2 virus. However, even despite having high levels of IgG antibodies against the S1 protein of the SARS-CoV-2 virus, (re-)infection may occur. We thus examined 2994 consecutive blood samples of outpatients from the Berlin-Brandenburg area in Germany in which IgG antibodies against the S1 protein of the SARS-CoV-2 virus as well as neutralizing SARS-CoV-2 virus antibodies were determined from the same sample. When analyzing the entire study population (2994 outpatients), we saw that S1 IgG antibodies (women: 223.98 ± 3.81; men: 207.80 ± 4.59; p = 0.014) and neutralizing antibodies (women: 66.65 ± 0.82; men: 62.88 ± 1.01; p = 0.021) are slightly higher in women than in men. Curve fitting revealed a good non-linear relationship between S1 IgG and neutralizing SARS-CoV-2 antibodies. However, 51 out of the 2994 blood samples from individual subjects were positive with regard to the neutralizing antibodies and at the same time negative for S1 IgG antibodies, and 112 out of the 2994 blood samples from individual subjects were negative with regard to the neutralizing antibodies and at the same time positive for S1 IgG antibodies. In conclusion, our study shows that there is a relevant number of patients who, despite developing significant titers of S1 antibodies, do not have relevant amounts of neutralizing antibody titers and are probably at high risk of (re-)infection.

Detection of SARS-CoV-2 Antibodies in Oral Fluid Using a Magnetic Particle-Based Chemiluminescence Immunoassay - Beijing Municipality, China, 2021.

Introduction: Oral fluids (OFs) have been broadly used as non-invasive samples for evaluating protective IgG antibodies from natural infection or vaccination, especially in pediatric populations. Methods: Paired OF and serum were collected from both individuals who received a booster dose of the inactive coronavirus disease 2019 (COVID-19) vaccine as well as those who did not have a history of COVID-19 vaccination and infection (as the control group). The total human IgG antibody (HIgG) content was evaluated as a marker of OF sampling quality. An in-house adapted magnetic particle-based chemiluminescence immunoassay was used for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibody detection in the OF. The SARS-CoV-2 IgG antibody in the serum samples was detected using a commercial immunoassay. Results: In total, 579 paired OF and serum samples were collected. An additional 172 OF samples were collected from preschool children. The results indicated that the HIgG concentration in qualified OF samples should be higher than 0.3 µg/mL. Compared to the serum assay, the in-house OF immunoassay for detecting IgG antibodies against SARS-CoV-2 had 95.06% accuracy, 95.03% sensitivity, and 100% specificity. Conclusions: Overall, the in-house immunoassay for detecting SARS-CoV-2 IgG antibodies in OF showed high potential for application towards serological surveillance and immunization effect assessment after large-scale, inactive COVID-19 vaccination in China.

Clinical Characteristics of Coronavirus Disease (COVID-19) in Mexican Children and Adolescents.

BACKGROUND: We analyzed the demographic, clinical, and diagnostic data of children and adolescents in Mexico, from the first case of coronavirus disease (COVID-19) to 28 February 2022. METHODS: Using the open databases of the Ministry of Health and a tertiary pediatric hospital, we obtained demographic and clinical data from the beginning of the COVID-19 pandemic until 28 February 2022. In addition, quantitative reverse-transcription polymerase chain reaction outputs were used to determine the viral load, and structural protein-based serology was performed to evaluate IgG antibody levels. RESULTS: Of the total 437,832 children and adolescents with COVID-19, 1187 died. Of these patients, 1349 were admitted to the Hospital Infantil de Mexico Federico Gómez, and 11 died. Obesity, asthma, and immunosuppression were the main comorbidities, and fever, cough, and headache were the main symptoms. In this population, many patients have a low viral load and IgG antibody levels. CONCLUSION: During the first 2 years of the COVID-19 pandemic in Mexico, children and adolescents had low incidence and mortality. They are a heterogeneous population, but many patients had comorbidities such as obesity, asthma, and immunosuppression; symptoms such as fever, cough, and headache; and low viral load and IgG antibodies.

Concordance of SARS-CoV-2 Antibody Results during a Period of Low Prevalence.

Accurate, highly specific immunoassays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to evaluate seroprevalence. This study investigated the concordance of results across four immunoassays targeting different antigens for sera collected at the beginning of the SARS-CoV-2 pandemic in the United States. Specimens from All of Us participants contributed between January and March 2020 were tested using the Abbott Architect SARS-CoV-2 IgG (immunoglobulin G) assay (Abbott) and the EuroImmun SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) (EI). Participants with discordant results, participants with concordant positive results, and a subset of concordant negative results by Abbott and EI were also tested using the Roche Elecsys anti-SARS-CoV-2 (IgG) test (Roche) and the Ortho-Clinical Diagnostics Vitros anti-SARS-CoV-2 IgG test (Ortho). The agreement and 95% confidence intervals were estimated for paired assay combinations. SARS-CoV-2 antibody concentrations were quantified for specimens with at least two positive results across four immunoassays. Among the 24,079 participants, the percent agreement for the Abbott and EI assays was 98.8% (95% confidence interval, 98.7%, 99%). Of the 490 participants who were also tested by Ortho and Roche, the probability-weighted percentage of agreement (95% confidence interval) between Ortho and Roche was 98.4% (97.9%, 98.9%), that between EI and Ortho was 98.5% (92.9%, 99.9%), that between Abbott and Roche was 98.9% (90.3%, 100.0%), that between EI and Roche was 98.9% (98.6%, 100.0%), and that between Abbott and Ortho was 98.4% (91.2%, 100.0%). Among the 32 participants who were positive by at least 2 immunoassays, 21 had quantifiable anti-SARS-CoV-2 antibody concentrations by research assays. The results across immunoassays revealed concordance during a period of low prevalence. However, the frequency of false positivity during a period of low prevalence supports the use of two sequentially performed tests for unvaccinated individuals who are seropositive by the first test. IMPORTANCE What is the agreement of commercial SARS-CoV-2 immunoglobulin G (IgG) assays during a time of low coronavirus disease 2019 (COVID-19) prevalence and no vaccine availability? Serological tests produced concordant results in a time of low SARS-CoV-2 prevalence and no vaccine availability, driven largely by the proportion of samples that were negative by two immunoassays. The CDC recommends two sequential tests for positivity for future pandemic preparedness. In a subset analysis, quantified antinucleocapsid and antispike SARS-CoV-2 IgG antibodies do not suggest the need to specify the antigen targets of the sequential assays in the CDC's recommendation because false positivity varied as much between assays targeting the same antigen as it did between assays targeting different antigens.