Progress in understanding the health promoting effect of egg yolk immunoglobulin

As an important immuneoactive component in eggs, yolk immunoglobulin (IgY) shows great competitiveness in research and production due to its good stability, high safety, low cost, easy availability, strong immune activity, and no drug resistance. This article highlights the significant advantages of IgY as a good antibiotic substitute in the prevention and treatment of viral and bacterial diseases. Also, IgY has great potential in the regulation of nutrient metabolism balance, intestinal microflora and immune homeostasis by affecting key rate-limiting enzymes, and relevant receptors and inflammatory factors specifically. Proper diet and targeted delivery of foodborne IgY may be a new perspective on inflammation regulation, disease control, nutritional balance or homeostasis, and oral microencapsulated IgY is expected to be a new approach against increasing public health emergencies (such as COVID-19 pandemic).

Evaluation of antibody levels for COVID-19 patients who attended a laboratory in Buenos Aires city

At the end of 2019 the first cases of SARS-CoV-2-associated pneumonia were reported in China. Consequently, the World Health Organization (WHO) named it COVID-19 and in January 2020, it declared the international health emergency due to the worldwide rapid spread of the infection. The first cases in Argentina were detected in early March 2020. Molecular tests like RT PCR and LAMP were immediately used. Serological tests for antibody detection were approved a few months later;however, these are still not the preferred diagnostic method for the disease. In our laboratory, the latter began to be used during the first wave of COVID-19. With the results obtained in that moment, an observational retrospective study in a cohort of patients who came voluntarily to test for SARS-CoV-2 IgG antibodies and whose results were positive was performed. The notification rate to the Argentine Integrated System for Health Information (SISA for its acronym in Spanish) was calculated and antibody levels were evaluated, clustering them according to the following facts: if the event had been notified to the SISA and if they had a previous RT PCR/LAMP result, the symptoms experienced by these patients and the time elapsed between RT PCR/LAMP and antibody test results. It was not possible to demonstrate differences between patients with detectable and undetectable RT PCR/LAMP, neither with the type of declared symptoms nor with respect to the days elapsed post-infection. However, it was found that there was a significant difference between notified and non-notified patients, and a high rate of non-notified patients with positive antibodies. Therefore, antibodies level might be considered as a surrogate marker of SARS-CoV-2 contact when a diagnosis through molecular methods is not available.

Retrospective Study on Vaccine Responses and Natural Course of COVID-19 Infections in Primary Immunodeficiency

We conducted a retrospective study in the adult primary immunodeficiency clinic at UAB examining COVID-19 infection and COVID-19 antibody response from vaccination, natural infection, and immunoglobulin replacement from February 2021 to November 2022. Our goal was to determine if nucleocapsid and spike antibodies could be found in our PID patients and if these antibodies could be derived from natural infection, vaccination, or antibody replacement exclusively or combinatory. We hypothesized that increasing antibodies would be detected in our population as the COVID period extended. Two hundred and forty-five subjects were tracked over 336 clinic visits during this period. Our PID population included subjects with CVID, XLA, thymoma, hypogammaglobulinemia, IgA deficiency, IgG subclass deficiency, specific antibody deficiency, Down syndrome, IgM deficiency, and patients with recurrent sinopulmonary infections. We had 196 females and 45 males in our study. In our patient population, 47% of our patient had known COVID-19 infection. Of those 47%, 21% of those infected patients had COVID-19 at least twice. Of those infected, three did not have COVID-19 spike antibodies and chose not to get vaccinated either. Two of those patients were not on IVIG and one was on Pangyza. Of those infected, 70% (n = 80) were on IgG infusions compared to those uninfected, 77% (n = 96) were on IgG infusions. Of interest, we had three XLA patients and all three had COVID-19 infection in the summer 2021. Two of them tested positive for nucleocapsid and spike antibodies in high titers and they were receiving Gammagard or Gamunex infusions, suggesting that these immunoglobulin preparations contain COVID-19 antibodies. We are still in the process of analyzing our data to see if diagnosis, IgG preparations, date of testing, B cell numbers, and drugs play a role in producing nucleocapsid antibodies and high spike antibody titers.Copyright © 2023 Elsevier Inc.

Detection of SARS-CoV-2 Antibodies in Matched Pregnant Women and Newborn Blood

Objective: The factors affecting the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies from mother to newborn and the duration of seropositivity rates in these infants have not yet been clearly demonstrated. The objectives of this study were (1) to assess the levels of SARS-CoV-2 spike-specific immunoglobulin G (IgG) in women infected in the pregnancy period and newborns born to these women and (2) to search the transplacental transfer ratio of spike-specific IgG. Method(s): Seventy pregnant women with symptomatic SARS-CoV-2 infection and their newborns were prospectively followed. Anti-SARS-CoV-2 immunoassay was used for the detection of the in vitro quantitative determination of total antibodies to the SARS-CoV-2 spike protein. Discussion(s): Spike-specific IgG was demonstrated in 89.1% (44 of 46) of pregnant women infected more than 14 days before delivery and in 92.6% (43 of 44) of their newborns. Median transfer ratio of spike-specific Ig was 0.87 (interquartile range [IQR], 0.34-0.90), 1.0 (IQR, 0.9-0.29), and 0.81 (IQR, 0.02-1.0) in first trimester (n = 4), second trimester (n = 14), and third trimester (n = 28) pregnant women, respectively. Antibody transfer ratio was correlated with time elapsed from infection (p < 0.001). Peak antibody transfer ratio above 1 was observed at a median 60 to 120 days after the infection from delivery. Antibody transfer ratio was high in pregnant women infected more than 60 days before delivery (p < 0.001). Transfer ratio was significantly higher in the severe-critically symptomatic women (n = 15) than the mild-moderately symptomatic women (n = 55) (p = 0.001). At 3 months, 18 of 25 infants (72%) had spike-specific IgG. Conclusion(s): Timing from infection to delivery and severity of maternal infection are critical in assessing the antibody generation and transport. Higher antibody transfer ratio can be detected in neonates when SARS-CoV-2 infection is present for more than 60 days before birth. Maternally derived antibody can persist for 3 months after birth.Copyright © 2023. The Author(s).

A cross-sectional study on the seroprevalence of the SARS-CoV-2 IgG antibody in patients with cancer from central Kerala

Background: Patients with cancer are vulnerable to coronavirus disease 2019 (COVID-19). Given the rising number of COVID-19 cases and relaxation of stringent COVID-19 protocols, assessment of the level of protective immunity to COVID-19 in patients with cancer has assumed importance. Objective(s): Our primary objective was to evaluate the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in patients with cancer. Material(s) and Method(s): We conducted a cross-sectional study on 100 patients with solid tumors attending our Oncology Department at the Believers Church Medical College, Kerala, India, between December 2020 and June 2021. Seroprevalence was assessed using the VITROS Anti-SARS-CoV-2 IgG test (Ortho-Clinical Diagnostics, Rochester, NY, USA). Additionally, we assessed the factors associated with seropositivity and collected data regarding the general experience of patients with cancer during the pandemic. Result(s): The median age of the participants was 62 years (IQR, 53-69.8);52 (52%) were males. The seroprevalence of the SARS-CoV-2 IgG antibodies was 11% (95% CI, 4.8-17.1). Age < 50 years was the only factor that was significantly associated with a higher rate of COVID-19 antibodies (77% vs 8.9% in patients >= 50 years;P = 0.007), and sex, smoking, and the use of alcohol did not show any association. The majority (77/100, 77%) of the patients were worried about contracting COVID-19 infection;some even deferred cancer-directed treatment because of the fear of visiting health care settings. Conclusion(s): Low seroprevalence of SARS-CoV-2 IgG antibodies in unvaccinated patients with cancer is a matter of concern as it indicates that many of these patients are still vulnerable to infection. There is an urgent need to continue implementing strict safety measures in oncology centers and to encourage widespread COVID-19 vaccination to prevent the uncontrolled spread of COVID-19 among patients with cancer. (Funded by the institution, Believers Church Medical College, Kerala).Copyright © 2023 Neurology India, Neurological Society of India Published by Wolters Kluwer - Medknow.

Association between diet quality and BMI with side effects of pfizer-biontech COVID-19 vaccine and SARS-CoV-2 immunoglobulin G titers. (Special Issue: The relationship between nutrition and COVID-19.)

Purpose: The nutritional and anthropometric status can be essential in determining their immune response to vaccines. The purpose of this paper was to investigate the association between diet quality and anthropometric indices with the side effects of the Pfizer-BioNTech COVID-19 vaccine and the SARS-CoV-2 immunoglobulin G titer among Kurdish adults. Design/methodology/approach: This cross-sectional survey-based study was conducted between December 2021 and February 2022. This paper included data on 115 adults, 20-89 years old, from the Kurdistan region. Dietary information was collected using a short food frequency questionnaire, and diet quality was assessed using a plant-based healthy diet score. A blood test was performed to measure the SARS-CoV-2 immunoglobin G (IgG) titer after the vaccination's first and second doses. Findings: Overweight and obese subjects reported more local pain, myalgia, headache, local bruising and local reactions after receiving the first dose of the vaccine (p = 0.04). People on a less healthy diet reported more local pain, myalgia and headache (p = 0.04) and more local bruising and reactions (p = 0.01) after receiving the second dose of the vaccine. On the other hand, the authors observed that those with healthy dietary habits had more IgG titer after the first and second doses of vaccination than those with less healthy dietary habits (p = 0.001). Originality/valueThe results showed that participants with a healthy diet and normal weight status had fewer side effects of the Pfizer-BioNTech COVID-19 vaccine than obese people and those with a less healthy diet.

Monitoring SARS CoV-2 antibodies positivity in healthcare workers after inactivated CoronaVac vaccine

Introduction In this study, we aimed to monitor anti-spike and anti-nucleocapsid antibodies positivity in healthcare workers (HCWs) vaccinated with two doses of inactivated CoronaVac (Sinovac, China) vaccine. Methods Overall, 242 volunteer HCWs were included. Of the participants, 193 were HCWs without history of prior documented COVID-19 (Group 1), while 49 had history of prior documented COVID-19 before vaccination (Group 2). The participants were followed up for SARS-CoV-2 antibodies positivity at four different blood sampling time points (immediately before the second vaccine dose and at the 1st, 3rd months and 141-150 days after the second dose). We investigated the serum IgG class antibodies against SARS-CoV-2 RBD region and IgG class antibodies against SARS-CoV-2 nucleocapsid antigen by chemiluminescent microparticle immunoassay (CMIA) method using commercial kits. Results We found positive serum anti-RBD IgG antibody in 76.4% of the participants (71% in Group 1;98% in Group 2) 28 days after the first dose. When the antibody levels of the groups were compared at the four blood sampling time points, Group 2 anti-RBD IgG levels were found to be significantly higher than those in Group 1 at all follow-up time points. Although anti-RBD IgG positivity persisted in 95.6% of all participants in the last blood sampling time point, a significant decrease was observed in antibody levels compared to the previous blood sampling time point. Anti-nucleocapsid IgG antibody was positive in 12 (6.2%) of participants in Group 1 and 32 (65.3%) in Group 2 at day 28 after the first dose. At the fourth blood sampling time point, anti-nucleocapsid antibodies were found to be positive in a total of 20 (9.7%) subjects, 10 (6.1%) in Group 1 and 10 (23.8%) in Group 2. Conclusions In this study, it was determined that serum antibody levels decreased in both groups after the third month after the second dose in HCWs vaccinated with CoronaVac vaccine.Copyright © GERMS 2022.

Seroprevalence of anti-SARS-CoV-2 antibodies in high-risk occupational and low-risk groups in southwestern Iran

Background: Monitoring the spread of SARS-CoV-2 has been considered by the World Health Organization (WHO). We examined the prevalence of anti-SARS-CoV-2 immunoglobulin antibodies in southwestern Iran in spring 2020. The circulation of SARS-CoV-2 is high in the general population, especially among health care workers (HCWs) who are in close contact with patients. Objectives: The aim of this study was to determine the prevalence of anti-SARS-CoV-2 antigen in high-risk occupational and low-risk groups to investigate risk factors for serum positivity in Shiraz, southwestern Iran. Methods: A cross-sectional survey was performed on 366 participants (204 from high-risk and 162 from low-risk subjects). IgG and IgM antibodies were detected using Pishtaz Teb COVID-19 ELISA Kits to evaluate SARS-CoV-2-antigen in serum samples. After enzyme-linked immunosorbent assay (ELISA), serum prevalence, as well as IgG/IgM positive factors, was determined using logistic regression. Results: From July to September 2020 (a few months after reporting the first case of COVID-19 cases in Iran), out of 366 survived people, 72 (40.9%) were IgG positive, and 50 (27.5%) were IgM positive. The frequency of positive serology for IgG and IgM antibodies in individuals aged < 30 years was higher in the low-risk group than in the high-risk group. Multivariate logistic regression showed that headache (OR 0.312 [95% CI: 0.136 - 0.717]) and cough (OR 0.427 [95% CI: 0.182 - 1.004]) factors were associated with IgG or IgM positive serology. Conclusions: Between July and September 2020, the prevalence of anti-SARS-CoV-2 antigen was high in Shiraz. The prevalence of SARS-CoV-2 IgG/IgM antibodies in the high-risk group and their family as low risk was shown to increase viral infection due to close contact with COVID 19 patients than in the general population. Several factors were found to be related to the prevalence of anti-SARS-CoV-2 antigen that needs to be considered by policymakers to determine what to do about the SARS-CoV-2 pandemic.

Special issue: The role of laboratory medicine in predicting the survival, progression and mortality of patients with corona virus disease 2019 (Covid-19). (Special issue: The role of laboratory medicine in predicting the survival, progression and mortality of patients with corona virus disease 2019 (Covid-19).)

This special issue contains 8 articles that explore various latest research on COVID-19, including the clinical presentation of the disease, the role of inflammation, the development of new treatments, and the long-term effects of the infection. The topics covered include the evaluation of white blood cell parameters and their significance in COVID-19 patients in Western Maharashtra, India;the association between acute phase reactants and COVID-19 severity and mortality in a tertiary care hospital in India;the clinico-hematological profile of COVID-19 patients from an Indian perspective;the correlation between C-reactive protein test results and clinical characteristics in COVID-19 patients;the effective binding affinity of an inhibitor against the SARS-CoV-2 NSP13 helicase;the assessment of absolute neutrophil count in COVID-19 patients in a tertiary care hospital;the analysis of the anti-SARS-CoV-2 IgG response following the first and second dose of a COVID-19 vaccine;and a case report discussing the diagnostic dilemma of hypoplastic acute myeloid leukemia in a COVID-19 patient.

IgG4 Antibodies Induced by Repeated Vaccination May Generate Immune Tolerance to the SARS-CoV-2 Spike Protein.

Less than a year after the global emergence of the coronavirus SARS-CoV-2, a novel vaccine platform based on mRNA technology was introduced to the market. Globally, around 13.38 billion COVID-19 vaccine doses of diverse platforms have been administered. To date, 72.3% of the total population has been injected at least once with a COVID-19 vaccine. As the immunity provided by these vaccines rapidly wanes, their ability to prevent hospitalization and severe disease in individuals with comorbidities has recently been questioned, and increasing evidence has shown that, as with many other vaccines, they do not produce sterilizing immunity, allowing people to suffer frequent re-infections. Additionally, recent investigations have found abnormally high levels of IgG4 in people who were administered two or more injections of the mRNA vaccines. HIV, Malaria, and Pertussis vaccines have also been reported to induce higher-than-normal IgG4 synthesis. Overall, there are three critical factors determining the class switch to IgG4 antibodies: excessive antigen concentration, repeated vaccination, and the type of vaccine used. It has been suggested that an increase in IgG4 levels could have a protecting role by preventing immune over-activation, similar to that occurring during successful allergen-specific immunotherapy by inhibiting IgE-induced effects. However, emerging evidence suggests that the reported increase in IgG4 levels detected after repeated vaccination with the mRNA vaccines may not be a protective mechanism; rather, it constitutes an immune tolerance mechanism to the spike protein that could promote unopposed SARS-CoV2 infection and replication by suppressing natural antiviral responses. Increased IgG4 synthesis due to repeated mRNA vaccination with high antigen concentrations may also cause autoimmune diseases, and promote cancer growth and autoimmune myocarditis in susceptible individuals.

Impact of pregnancy on polyfunctional IgG and memory B cell responses to Tdap immunization.

BACKGROUND: Maternal pertussis immunization using Tdap vaccine is recommended in many countries to protect newborns from severe post-natal infection. Immunological changes during pregnancy may influence the response to vaccines. The quality of IgG and memory B cell responses to Tdap immunization in pregnant women has not yet been described. METHODS: The impact of pregnancy on the response to Tdap vaccination was assessed by comparing humoral immune responses in 42 pregnant and 39 non-pregnant women. The levels of serum pertussis antigens and tetanus toxoid-specific IgG, IgG subclasses, IgG Fc-mediated effector functions, as well as memory B cell frequencies were assessed before and at several time points after vaccination. RESULTS: Tdap immunization induced similar levels of pertussis and tetanus-specific IgG and IgG subclasses in pregnant and non-pregnant women. Pregnant women produced IgG promoting complement deposition, and neutrophils and macrophages phagocytosis at levels comparable to non-pregnant women. They were also able to expand pertussis and tetanus-specific memory B cells at similar frequencies as non-pregnant women, suggesting equivalent "boostability". Higher levels of vaccine-specific IgG, IgG subclasses, and IgG Fc-mediated effector functions were detected in cord blood as compared to maternal blood, indicating efficient transport across the placenta. CONCLUSIONS: This study demonstrates that pregnancy does not affect the quality of effector IgG and memory B cell responses to Tdap immunization and that polyfunctional IgG are efficiently transferred across the placenta. REGISTRY'S URL AND THE TRIAL'S REGISTRATION NUMBER: ClinicalTrials.Gov (NCT03519373).

Noncovalent antibody catenation on a target surface greatly increases the antigen-binding avidity.

Immunoglobulin G (IgG) antibodies are widely used for diagnosis and therapy. Given the unique dimeric structure of IgG, we hypothesized that, by genetically fusing a homodimeric protein (catenator) to the C-terminus of IgG, reversible catenation of antibody molecules could be induced on a surface where target antigen molecules are abundant, and that it could be an effective way to greatly enhance the antigen-binding avidity. A thermodynamic simulation showed that quite low homodimerization affinity of a catenator, e.g. dissociation constant of 100 µM, can enhance nanomolar antigen-binding avidity to a picomolar level, and that the fold enhancement sharply depends on the density of the antigen. In a proof-of-concept experiment where antigen molecules are immobilized on a biosensor tip, the C-terminal fusion of a pair of weakly homodimerizing proteins to three different antibodies enhanced the antigen-binding avidity by at least 110 or 304 folds from the intrinsic binding avidity. Compared with the mother antibody, Obinutuzumab(Y101L) which targets CD20, the same antibody with fused catenators exhibited significantly enhanced binding to SU-DHL5 cells. Together, the homodimerization-induced antibody catenation would be a new powerful approach to improve antibody applications, including the detection of scarce biomarkers and targeted anticancer therapies.

Humoral and cellular immune response to SARS-CoV-2 mRNA BNT162b2 vaccine in pediatric kidney transplant recipients compared with dialysis patients and healthy children.

BACKGROUND: Compared with the general population, the immune response to COVID-19 mRNA vaccines is lower in adult kidney transplant recipients (KTRs). However, data is limited for pediatric KTRs. In this study, we aimed to assess humoral and cellular immune responses to the COVID-19 mRNA vaccine in pediatric KTRs. METHODS: This multicenter, prospective, case-control study included 63 KTRs (37 male, aged 12-21 years), 19 dialysis patients, and 19 controls. Humoral (anti-SARS-CoV2 IgG, neutralizing Ab (nAb)) and cellular (interferon-gamma release assay (IGRA)) immune responses were assessed at least one month after two doses of BNT162b2 mRNA vaccine. RESULTS: Among COVID-19 naïve KTRs (n = 46), 76.1% tested positive for anti-SARS-CoV-2 IgG, 54.3% for nAb, and 63% for IGRA. Serum levels of anti-SARS-CoV-2 IgG and nAb activity were significantly lower in KTRs compared to dialysis and control groups (p < 0.05 for all). Seropositivity in KTRs was independently associated with shorter transplant duration (p = 0.005), and higher eGFR (p = 0.007). IGRA titer was significantly lower than dialysis patients (p = 0.009). Twenty (43.4%) KTRs were positive for all immune parameters. Only four of 11 seronegative KTRs were IGRA-positive. COVID-19 recovered KTRs had significantly higher anti-SARS-CoV-2 IgG and nAb activity levels than COVID-19 naïve KTRs (p = 0.018 and p = 0.007, respectively). CONCLUSIONS: The humoral and cellular immune responses to SARS-CoV-2 mRNA BNT162b2 vaccine are lower in pediatric KTRs compared to dialysis patients. Further prospective studies are required to demonstrate the clinical efficacy of the mRNA vaccine in KTRs. This prospective study was registered in ClinicalTrials.gov (NCT05465863, registered retrospectively at 20.07.2022). A higher resolution version of the Graphical abstract is available as Supplementary information.

A single dose of COVID-19 vaccine induces a strong T cell and B cell response in healthcare professionals recovered from SARS-CoV-2 infection.

A broad understanding on how SARS-CoV-2 infection and vaccination mobilize the immune system is necessary to find the best predictors of long-term protection and identify individuals that would benefit from additional vaccine doses. This study aims to understand the effect of a single dose of Pfizer-BioNTech BNT162b2 COVID-19 vaccine, in individuals recovered from SARS-CoV-2 infection, on circulating CD4+ T follicular helper (Tfh)-cells, Spike-specific T-cells and IgG/IgA antibodies. For that, peripheral blood samples from 50 healthcare professionals, recovered from SARS-CoV-2 infection, collected immediately before (T1) and 15 days after (T2) vaccine administration, were used to analyze the frequency and numbers of Tfh-cells and their subsets, serum titers of SARS-CoV-2-specific antibodies, and SARS-CoV-2-specific T-cells. Six months after infection (T1), 96% of recovered participants presented either IgG or T-cells specific for Spike, however, Spike-specific T-cells were missing in 16% of them. These individuals presented lower levels of Spike-specific IgG (T1 and T2), IgA (T1), and Spike-specific T-cells (T2). Vaccination increased the percentage of participants reactive for Spike-specific T-cells (from 64 to 98%), IgG (from 90 to 100%) and IgA (from 48 to 98%). It also mobilized circulating Tfh-cells, increasing their frequency and activation, and promoting Tfh17 polarization, restoring the decreased numbers of Tfh-cells (especially Tfh17) observed in recovered participants. Interestingly, Tfh percentage correlated with Spike-specific IgG levels. Our data showed that a single dose of vaccine efficiently restored Spike-specific T-cells, and IgG and IgA antibodies. Mobilization of Tfh-cells, and their correlation with IgG levels, suggest that vaccination induced a functional Tfh cell response.

Age, Sex and BMI Relations with Anti-SARS-CoV-2-Spike IgG Antibodies after BNT162b2 COVID-19 Vaccine in Health Care Workers in Northern Greece.

The aim of this work was to study age, sex, and BMI (Body Mass Index)-related differences in the development of anti-SARS-CoV-2-Spike IgG antibodies, after vaccination with the BNT162b2 COVID-19 vaccine, in health care workers of a General Hospital in a city in Northern Greece. Blood sampling was drawn two to four weeks following the second dose of the vaccine, and six months after the first blood sample collection. Measurement of serum IgG antibodies against the spike domain of SARS-CoV-2 was performed using the SARS-CoV-2 IgG II Quant assay. All participants had sufficient serum IgG titers in the first measurement. Women developed higher IgG titers than men. The IgG titers were inversely related to age in both sexes; there was also a small, insignificant tendency to be inversely related to BMI. Six months after the first measurement, the IgG titers decreased dramatically to values less than 5% of the initial. This decrease was observed in both men and women and was inversely related to age. Multivariate regression analysis showed that age and sex explained with statistical significance 9% of the variance in SARS-CoV-2 IgG titers in our study population; the role of BMI was limited and insignificant.

Comparing Heterologous and Homologous COVID-19 Vaccination: A Longitudinal Study of Antibody Decay.

The humoral response after vaccination was evaluated in 1248 individuals who received different COVID-19 vaccine schedules. The study compared subjects primed with adenoviral ChAdOx1-S (ChAd) and boosted with BNT162b2 (BNT) mRNA vaccines (ChAd/BNT) to homologous dosing with BNT/BNT or ChAd/ChAd vaccines. Serum samples were collected at two, four and six months after vaccination, and anti-Spike IgG responses were determined. The heterologous vaccination induced a more robust immune response than the two homologous vaccinations. ChAd/BNT induced a stronger immune response than ChAd/ChAd at all time points, whereas the differences between ChAd/BNT and BNT/BNT decreased over time and were not significant at six months. Furthermore, the kinetic parameters associated with IgG decay were estimated by applying a first-order kinetics equation. ChAd/BNT vaccination was associated with the longest time of anti-S IgG negativization and with a slow decay of the titer over time. Finally, analyzing factors influencing the immune response by ANCOVA analysis, it was found that the vaccine schedule had a significant impact on both the IgG titer and kinetic parameters, and having a Body Mass Index (BMI) above the overweight threshold was associated with an impaired immune response. Overall, the heterologous ChAd/BNT vaccination may offer longer-lasting protection against SARS-CoV-2 than homologous vaccination strategies.

Enhancing immune protection against MERS-CoV: the synergistic effect of proteolytic cleavage sites and the fusion peptide and RBD domain targeting VLP immunization.

Introduction: The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a zoonotic infectious virus that has caused significant outbreaks in the Middle East and beyond. Due to a highly mortality rate, easy transmission, and rapid spread of the MERS-CoV, it remains as a significant public health treat. There is currently no licensed vaccine available to protect against MERS-CoV. Methods: In this study, we investigated whether the proteolytic cleavage sites and fusion peptide domain of the MERS-CoV spike (S) protein could be a vaccine target to elicit the MERS-CoV S protein-specific antibody responses and confer immune protection against MERS-CoV infection. Our results demonstrate that immunization of the proteolytic cleavage sites and the fusion peptide domain using virus-like particle (VLP) induced the MERS-CoV S protein-specific IgG antibodies with capacity to neutralize pseudotyped MERS-CoV infection in vitro. Moreover, proteolytic cleavage sites and the fusion peptide VLP immunization showed a synergistic effect on the immune protection against MERS-CoV infection elicited by immunization with VLP expressing the receptor binding domain (RBD) of the S protein. Additionally, immune evasion of MERS-CoV RBD variants from anti-RBD sera was significantly controlled by anti-proteolytic cleavage sites and the fusion peptide sera. Conclusion and discussion: Our study demonstrates the potential of VLP immunization targeting the proteolytic cleavage sites and the fusion peptide and RBD domains of the MERS-CoV S protein for the development of effective treatments and vaccines against MERS-CoV and related variants.

Multisystem Inflammatory Syndrome in Children (MIS-C), Possibly Due to COVID-19 mRNA Vaccination.

Multisystem inflammatory syndrome in children (MIS-C) is a potentially life-threatening childhood disease caused by SARS-CoV-2 infection, manifested by the persistence of fever and multi-organ dysfunction, elevated inflammatory markers, and the lack of an alternative diagnosis. It is still unknown if vaccination can precipitate or abrogate MIS-C or if a natural infection preceding or occurring at the time of vaccination plays any role. We present one case of MIS-C in a 16-year-old girl who was fully immunized against COVID-19 (Pfizer), with the second dose received three weeks prior to onset of the disease. She had no history of COVID-19 disease or contact with COVID-19 patients. At admission, she was somnolent, pale, and dehydrated, with cyanotic lips and cold extremities; she was hypotensive with tachycardia and poorly palpable pulses. Initial laboratory results revealed elevated levels of inflammatory markers, and high level of SARS-CoV-2 IgG spike antibodies, while testing for SARS-CoV-2 acute infection and other inflammatory etiologies were negative. Vaccine-related MIS-C was suspected in our case due to the development of MIS-C three weeks following the second dose of the COVID-19 mRNA vaccine, the absence of previous infection or exposure to SARS-CoV-2, and a positive result for IgG anti-spike (S) antibodies.

Long COVID and Hybrid Immunity among Children and Adolescents Post-Delta Variant Infection in Thailand.

This study aimed to assess long COVID, and describe immunogenicity against Omicron variants following BNT162b2 vaccination. A prospective cohort study was conducted among children (aged 5-11) and adolescents (aged 12-17) who had SARS-CoV-2 infection from July to December 2021 (Delta predominant period). Long COVID symptoms were assessed by questionnaires at 3 months after infection. Immunogenicity was evaluated by using a surrogate virus-neutralizing antibody test (sVNT) against the Omicron variant. We enrolled 97 children and 57 adolescents. At 3 months, 30 children (31%) and 34 adolescents (60%) reported at least one long COVID symptom, with respiratory symptoms prevailing (25% children and 32% adolescents). The median time from infection to vaccination was 3 months in adolescents and 7 months in children. At 1 month following vaccination, in children who received one-dose and two-dose BNT162b2 vaccines, the median (IQR) sVNT against Omicron was 86.2% inhibition (71.1-91.8) and 79.2% inhibition (61.5-88.9), respectively (p = 0.26). Among adolescents who received one-dose and two-dose BNT162b2 vaccines, the median (IQR) sVNT against Omicron was 64.4% inhibition (46.8-88.8) and 68.8% inhibition (65.0-91.2) (p = 0.64). Adolescents had a higher prevalence of long COVID than children. Immunogenicity against the Omicron variant after vaccination was high and did not vary between one or two doses of the vaccine in either children or adolescents.