Parvovirus B19 DNA and antibodies in Chinese plasma donors, plasma pools and plasma derivatives.

Background: Human parvovirus B19 (B19V) is a common contaminant found in plasma pools and plasma derivatives. Previous studies were mainly focused on limited aspects, further assessment of prevalence of B19V DNA and antibodies in plasma donors, the contamination of B19V in pooled plasma and plasma derivatives should be performed in China. Study Design and Methods: Individual plasma donors' samples from four provinces and pooled plasma from four Chinese blood product manufacturers were collected and screened using B19V DNA diagnostic kits between October 2018 and May 2020. The positive samples were investigated for the seroprevalence of B19V antibodies and subjected to sequence analysis and alignment for phylogenetic studies. Moreover, 11 plasma donors who were B19V DNA-positive at their first testing were also followed during the later donation period. Additionally, 400 plasma pools and 20 batches of plasma derivatives produced by pooled plasma with a viral load of B19V DNA exceeding 104IU/mL were also collected and tested for B19V DNA and antibodies. Objectives: To comprehensively and systematically determine the frequency and viral load of B19V DNA in plasma donors, pooled plasma, and plasma derivatives from four Chinese blood product manufacturers. Results: A total of 17,187 plasma donors were analyzed and 44 (0.26%) specimens were found positive for B19V DNA. The quantitative DNA levels ranged from 1.01 × 101 to 5.09 × 1012 IU/mL. Forty-four DNA-positive specimens were also investigated for the seroprevalence of B19V antibodies, 75.0% and 2.3% of which were seropositive for B19V IgG and IgM antibodies, respectively. The phylogenic analyses showed that the prevalent genotypes in the four provinces' plasma donors belonged to B19V Genotype 1. Eleven individual plasma donors who were B19V DNA-positive at the first donation were then followed for a period, and in general, the DNA levels of B19V gradually decreased. Moreover, 64.8% (259/400) of the pooled plasma was contaminated by B19V, with concentrations of 1.05 × 100-3.36 × 109IU/mL. Approximately 72.6% of the DNA-positive plasma pools were only moderately contaminated (<104 IU/mL), while 27.4% contained >104 IU/mL. Twenty batches of plasma derivatives produced by pooled plasma with a viral load of B19V DNA exceeding 104IU/mL were also tested. B19V was detected in 5/5 PCC samples and 5/5 factor VIII samples but was not found in the intravenous immune globulin and albumin samples. Conclusion: The contamination of B19V in pooled plasma and plasma-derived clotting factor concentrates is serious. Whether B19V nucleic acid testing (NAT) screening of plasma and plasma derivatives is launched in China, blood product manufacturers should spontaneously perform B19V NAT screening in plasma donors and mini-pool plasma. These measures can ensure that samples with high titer B19V DNA are discarded in order to prevent and control this transfusion transmitted virus.

Transplacental transfer of anti-SARS-CoV-2 neutralizing antibodies in comparison to other pathogens total antibodies.

BACKGROUNDS: Due to immaturity of their immune system, passive maternal immunization is essential for newborns during their first months of life. Therefore, in the current context of intense circulation of SARS-CoV-2, identifying factors influencing the transfer ratio (TR) of neutralizing antibodies against SARS-CoV-2 (NAb) appears important. METHODS: Our study nested in the COVIPREG cohort (NCT04355234), included mothers who had a SARS-CoV-2 PCR positive during their pregnancy and their newborns. Maternal and neonatal NAb levels were measured with the automated iFlash system. RESULTS: For the 173 mother-infant pairs included in our study, the median gestational age (GA) at delivery was 39.4 weeks of gestation (WG), and 29.7 WG at maternal SARS-CoV-2 infection. Using a multivariate logistic model, having a NAb TR above 1 was positively associated with a longer delay from maternal positive SARS-CoV-2 PCR to delivery (aOR 1.09, 95% CI: 1.03 - 1.17) and with a later GA at delivery (aOR = 1.58, 95% CI: 1.09 - 2.52). It was negatively associated with being a male newborn (aOR 0.21, 95% CI: 0.07 - 0.59). In 3rd trimester SARS-CoV-2 infected mothers, NAb TR was inferior to VZV, toxoplasmosis, CMV, measle and rubella's TR. However, in 1st or 2nd trimester infected mothers, only measle TR was different from NAb TR. CONCLUSION: Male newborn of mothers infected by SARS-CoV-2 during their pregnancy appear to have less protection against SARS-CoV-2 in their first months of life than female newborns. Measle TR was superior to NAb TR even in case of 1st or 2nd trimester maternal SARS-CoV-2 infection. Future studies are needed to investigate possible differences in transmission of NAb following infection vs vaccination and its impact on TR.

Prevalence of Anti-Human Herpes Virus Type 7 IgG Positivity Rate among Children with Fever and Skin Rash in Diyala Province, Iraq.

Human herpesvirus 7 (HHV-7) is a T-lymphotropic virus isolated from peripheral blood mononuclear cells as beta herpes viruses. It is a highly prevalent virus since over 90% of adults are seropositive. The majority of primary infection occurs in early childhood, and its prevalence peaks at 60 % in 11-13-year-old. This study was designed to investigate the seroprevalence of HHV- 7 infections among apparently healthy children as well as child patients with fever and skin rash in the Diyala community and its association with certain socio-demographic variables. The current study is a cross-sectional study conducted in Diyala province-Iraq, extending from July 2020 to March 2021. A total of 180 child patients with fever and skin rash were included. Their age range was 1-14years. Additionally, 60 healthy age-matched children were enrolled as a control group. A special questionnaire was prepared for this study, including socio-demographic information, clinical notes and the results of a complete blood count. Human privacy was esteemed by obtaining parents' verbal approval. Blood specimen was aspirated from all study groups. Sera were separated and kept at -20 °C until tested. Enzyme-linked immunosorbent assay (ELISA) kits for the detection of anti-HHV-7 IgG were used (Mybiosource-China). Statistical analysis was done using Statistical Package of Social Science (SPSS) version 27, and the P value was considered significant wherever it was less than 0.05. The anti-HHV-7 IgG positivity rate in patients was 19.4%, and that in healthy individuals was 31.7%, with an insignificant difference (P=0.051). The highest HHV-7 IgG positivity rate was found among patients 1-4 years old, matching that in the healthy group with a statistically insignificant difference (P=0.675). The gender, residence and number of children/ family insignificantly affect the distribution of HHV-7 IgG in the control group. The mean±SD of hemoglobulin (Hb) concentration among participants with negative anti-HHV-7 IgG was insignificant compared to their positive counterparts (P=0.987). The mean±SD of total WBC count among those positive for anti-HHV-7 IgG was insignificantly higher than their negative counterpart (P=0.945). The mean±SD lymphocyte count in patients and healthy control positive for anti-HHV-7 IgG were insignificantly higher (P=0.241) and (P=0.344), respectively. Lastly, healthy control positive for anti-HHV-7 IgG had insignificantly higher lymphocyte count (P=0.710). About one-third of healthy children in our community were seropositive for anti-HHV 7 IgG antibodies that are most prevalent at 1-4 years old and are insignificantly associated with gender, residence, and the number of children per family. Furthermore, the HHV-7 infection is insignificantly associated with alterations of complete blood count parameters.

Association between reactogenicity and immunogenicity after BNT162b2 booster vaccination: a secondary analysis of a prospective cohort study.

OBJECTIVES: A weak correlation between symptom severity and antibody levels after primary immunization against COVID-19 has already been shown. This study aimed to describe the association between reactogenicity and immunogenicity after booster vaccination. METHODS: This secondary analysis of a prospective cohort study included 484 healthcare workers who received a booster vaccination with BNT162b2. Anti-receptor binding domain (RBD) antibodies were assessed at baseline and 28 days after booster vaccination. Side effects were graded (none, mild, moderate, or severe) and reported daily for 7 days after booster vaccination. Spearman correlation coefficient (rho) was used to determine the correlations between the severity of each symptom and anti-RBD levels before vaccination and 28 days after. The Bonferroni method was used to adjust p values for multiple comparisons. RESULTS: Most of the 484 participants reported at least one local (451 [93.2%]) or systemic (437 [90.3%]) post-booster symptom. No correlations between the severity of local symptoms and antibody levels were found. Except for nausea, systemic symptoms showed weak but statistically significant correlations with 28-day anti-RBD levels (fatigue [rho = 0.23, p < 0.01], fever [rho = 22, p < 0.01], headache [rho = 0.15, p 0.03], arthralgia [rho = 0.2, p < 0.01], myalgia [rho = 0.17, p < 0.01]). There was no association between post-booster symptoms and pre-booster antibody levels. DISCUSSION: This study showed only a weak correlation between the severity of systemic post-booster symptoms and anti-SARS-CoV-2 antibody levels at 28 days. Therefore, self-reported symptom severity cannot be used to predict immunogenicity after booster vaccination.

Effect of Passive Administration of Monoclonal Antibodies Recognizing Simian Immunodeficiency Virus (SIV) V2 in CH59-Like Coil/Helical or ß-Sheet Conformations on Time of SIVmac251 Acquisition.

The monoclonal antibodies (MAbs) NCI05 and NCI09, isolated from a vaccinated macaque that was protected from multiple simian immunodeficiency virus (SIV) challenges, both target an overlapping, conformationally dynamic epitope in SIV envelope variable region 2 (V2). Here, we show that NCI05 recognizes a CH59-like coil/helical epitope, whereas NCI09 recognizes a ß-hairpin linear epitope. In vitro, NCI05 and, to a lesser extent, NCI09 mediate the killing of SIV-infected cells in a CD4-dependent manner. Compared to NCI05, NCI09 mediates higher titers of antibody-dependent cellular cytotoxicity (ADCC) to gp120-coated cells, as well as higher levels of trogocytosis, a monocyte function that contributes to immune evasion. We also found that passive administration of NCI05 or NCI09 to macaques did not affect the risk of SIVmac251 acquisition compared to controls, demonstrating that these anti-V2 antibodies alone are not protective. However, NCI05 but not NCI09 mucosal levels strongly correlated with delayed SIVmac251 acquisition, and functional and structural data suggest that NCI05 targets a transient state of the viral spike apex that is partially opened, compared to its prefusion-closed conformation. IMPORTANCE Studies suggest that the protection against SIV/simian-human immunodeficiency virus (SHIV) acquisition afforded by the SIV/HIV V1 deletion-containing envelope immunogens, delivered by the DNA/ALVAC vaccine platform, requires multiple innate and adaptive host responses. Anti-inflammatory macrophages and tolerogenic dendritic cells (DC-10), together with CD14+ efferocytes, are consistently found to correlate with a vaccine-induced decrease in the risk of SIV/SHIV acquisition. Similarly, V2-specific antibody responses mediating ADCC, Th1 and Th2 cells expressing no or low levels of CCR5, and envelope-specific NKp44+ cells producing interleukin 17 (IL-17) also are reproducible correlates of decreased risk of virus acquisition. We focused on the function and the antiviral potential of two monoclonal antibodies (NCI05 and NCI09) isolated from vaccinated animals that differ in antiviral function in vitro and recognize V2 in a linear (NCI09) or coil/helical (NCI05) conformation. We demonstrate that NCI05, but not NCI09, delays SIVmac251 acquisition, highlighting the complexity of antibody responses to V2.

Monitoring of SARS-CoV-2 Infection in Ragusa Area: Next Generation Sequencing and Serological Analysis.

The coronavirus disease 19 (COVID-19) post pandemic evolution is correlated to the development of new variants. Viral genomic and immune response monitoring are fundamental to the surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Since 1 January to 31 July 2022, we monitored the SARS-CoV-2 variants trend in Ragusa area sequencing n.600 samples by next generation sequencing (NGS) technology: n.300 were healthcare workers (HCWs) of ASP Ragusa. The evaluation of anti-Nucleocapside (N), receptor-binding domain (RBD), the two subunit of S protein (S1 and S2) IgG levels in 300 exposed vs. 300 unexposed HCWs to SARS-CoV-2 was performed. Differences in immune response and clinical symptoms related to the different variants were investigated. The SARS-CoV-2 variants trend in Ragusa area and in Sicily region were comparable. BA.1 and BA.2 were the most representative variants, whereas the diffusion of BA.3 and BA.4 affected some places of the region. Although no correlation was found between variants and clinical manifestations, anti-N and anti-S2 levels were positively correlated with an increase in the symptoms number. SARS-CoV-2 infection induced a statistically significant enhancement in antibody titers compared to that produced by SARS-CoV-2 vaccine administration. In post-pandemic period, the evaluation of anti-N IgG could be used as an early marker to identify asymptomatic subjects.

Combining Phage Display Technology with In Silico-Designed Epitope Vaccine to Elicit Robust Antibody Responses against Emerging Pathogen Tilapia Lake Virus.

Antigen epitope identification is a critical step in the vaccine development process and is a momentous cornerstone for the development of safe and efficient epitope vaccines. In particular, vaccine design is difficult when the function of the protein encoded by the pathogen is unknown. The genome of Tilapia lake virus (TiLV), an emerging virus from fish, encodes protein functions that have not been elucidated, resulting in a lag and uncertainty in vaccine development. Here, we propose a feasible strategy for emerging viral disease epitope vaccine development using TiLV. We determined the targets of specific antibodies in serum from a TiLV survivor by panning a Ph.D.-12 phage library, and we identified a mimotope, TYTTRMHITLPI, referred to as Pep3, which provided protection against TiLV after prime-boost vaccination; its immune protection rate was 57.6%. Based on amino acid sequence alignment and structure analysis of the target protein from TiLV, we further identified a protective antigenic site (399TYTTRNEDFLPT410) which is located on TiLV segment 1 (S1). The epitope vaccine with keyhole limpet hemocyanin (KLH-S1399-410) corresponding to the mimotope induced the tilapia to produce a durable and effective antibody response after immunization, and the antibody depletion test confirmed that the specific antibody against S1399-410 was necessary to neutralize TiLV. Surprisingly, the challenge studies in tilapia demonstrated that the epitope vaccine elicited a robust protective response against TiLV challenge, and the survival rate reached 81.8%. In conclusion, this study revealed a concept for screening antigen epitopes of emerging viral diseases, providing promising approaches for development and evaluation of protective epitope vaccines against viral diseases. IMPORTANCE Antigen epitope determination is an important cornerstone for developing efficient vaccines. In this study, we attempted to explore a novel approach for epitope discovery of TiLV, which is a new virus in fish. We investigated the immunogenicity and protective efficacy of all antigenic sites (mimotopes) identified in serum of primary TiLV survivors by using a Ph.D.-12 phage library. We also recognized and identified the natural epitope of TiLV by bioinformatics, evaluated the immunogenicity and protective effect of this antigenic site by immunization, and revealed 2 amino acid residues that play important roles in this epitope. Both Pep3 and S1399-410 (a natural epitope identified by Pep3) elicited antibody titers in tilapia, but S1399-410 was more prominent. Antibody depletion studies showed that anti-S1399-410-specific antibodies were essential for neutralizing TiLV. Our study demonstrated a model for combining experimental and computational screens to identify antigen epitopes, which is attractive for epitope-based vaccine development.

Efficacy and Safety of an Ad26.RSV.preF-RSV preF Protein Vaccine in Older Adults.

BACKGROUND: Respiratory syncytial virus (RSV) can cause serious lower respiratory tract disease in older adults, but no licensed RSV vaccine currently exists. An adenovirus serotype 26 RSV vector encoding a prefusion F (preF) protein (Ad26.RSV.preF) in combination with RSV preF protein was previously shown to elicit humoral and cellular immunogenicity. METHODS: We conducted a randomized, double-blind, placebo-controlled, phase 2b, proof-of-concept trial to evaluate the efficacy, immunogenicity, and safety of an Ad26.RSV.preF-RSV preF protein vaccine. Adults who were 65 years of age or older were randomly assigned in a 1:1 ratio to receive vaccine or placebo. The primary end point was the first occurrence of RSV-mediated lower respiratory tract disease that met one of three case definitions: three or more symptoms of lower respiratory tract infection (definition 1), two or more symptoms of lower respiratory tract infection (definition 2), and either two or more symptoms of lower respiratory tract infection or one or more symptoms of lower respiratory tract infection plus at least one systemic symptom (definition 3). RESULTS: Overall, 5782 participants were enrolled and received an injection. RSV-mediated lower respiratory tract disease meeting case definitions 1, 2, and 3 occurred in 6, 10, and 13 vaccine recipients and in 30, 40, and 43 placebo recipients, respectively. Vaccine efficacy was 80.0% (94.2% confidence interval [CI], 52.2 to 92.9), 75.0% (94.2% CI, 50.1 to 88.5), and 69.8% (94.2% CI, 43.7 to 84.7) for case definitions 1, 2, and 3, respectively. After vaccination, RSV A2 neutralizing antibody titers increased by a factor of 12.1 from baseline to day 15, a finding consistent with other immunogenicity measures. Percentages of participants with solicited local and systemic adverse events were higher in the vaccine group than in the placebo group (local, 37.9% vs. 8.4%; systemic, 41.4% vs. 16.4%); most adverse events were mild to moderate in severity. The frequency of serious adverse events was similar in the vaccine group and the placebo group (4.6% and 4.7%, respectively). CONCLUSIONS: In adults 65 years of age or older, Ad26.RSV.preF-RSV preF protein vaccine was immunogenic and prevented RSV-mediated lower respiratory tract disease. (Funded by Janssen Vaccines and Prevention; CYPRESS ClinicalTrials.gov number, NCT03982199.).

Evaluation of BNT162b2 Covid-19 Vaccine in Children Younger than 5 Years of Age.

BACKGROUND: Safe and effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in young children. METHODS: We conducted a phase 1 dose-finding study and are conducting an ongoing phase 2-3 safety, immunogenicity, and efficacy trial of the BNT162b2 vaccine in healthy children 6 months to 11 years of age. We present results for children 6 months to less than 2 years of age and those 2 to 4 years of age through the data-cutoff dates (April 29, 2022, for safety and immunogenicity and June 17, 2022, for efficacy). In the phase 2-3 trial, participants were randomly assigned (in a 2:1 ratio) to receive two 3-µg doses of BNT162b2 or placebo. On the basis of preliminary immunogenicity results, a third 3-µg dose (≥8 weeks after dose 2) was administered starting in January 2022, which coincided with the emergence of the B.1.1.529 (omicron) variant. Immune responses at 1 month after doses 2 and 3 in children 6 months to less than 2 years of age and those 2 to 4 years of age were immunologically bridged to responses after dose 2 in persons 16 to 25 years of age who received 30 µg of BNT162b2 in the pivotal trial. RESULTS: During the phase 1 dose-finding study, two doses of BNT162b2 were administered 21 days apart to 16 children 6 months to less than 2 years of age (3-µg dose) and 48 children 2 to 4 years of age (3-µg or 10-µg dose). The 3-µg dose level was selected for the phase 2-3 trial; 1178 children 6 months to less than 2 years of age and 1835 children 2 to 4 years of age received BNT162b2, and 598 and 915, respectively, received placebo. Immunobridging success criteria for the geometric mean ratio and seroresponse at 1 month after dose 3 were met in both age groups. BNT162b2 reactogenicity events were mostly mild to moderate, with no grade 4 events. Low, similar incidences of fever were reported after receipt of BNT162b2 (7% among children 6 months to <2 years of age and 5% among those 2 to 4 years of age) and placebo (6 to 7% among children 6 months to <2 years of age and 4 to 5% among those 2 to 4 years of age). The observed overall vaccine efficacy against symptomatic Covid-19 in children 6 months to 4 years of age was 73.2% (95% confidence interval, 43.8 to 87.6) from 7 days after dose 3 (on the basis of 34 cases). CONCLUSIONS: A three-dose primary series of 3-µg BNT162b2 was safe, immunogenic, and efficacious in children 6 months to 4 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

Molecular fate-mapping of serum antibody responses to repeat immunization.

The protective efficacy of serum antibodies results from the interplay of antigen-specific B cell clones of different affinities and specificities. These cellular dynamics underlie serum-level phenomena such as original antigenic sin (OAS)-a proposed propensity of the immune system to rely repeatedly on the first cohort of B cells engaged by an antigenic stimulus when encountering related antigens, in detriment to the induction of de novo responses1-5. OAS-type suppression of new, variant-specific antibodies may pose a barrier to vaccination against rapidly evolving viruses such as influenza and SARS-CoV-26,7. Precise measurement of OAS-type suppression is challenging because cellular and temporal origins cannot readily be ascribed to antibodies in circulation; its effect on subsequent antibody responses therefore remains unclear5,8. Here we introduce a molecular fate-mapping approach with which serum antibodies derived from specific cohorts of B cells can be differentially detected. We show that serum responses to sequential homologous boosting derive overwhelmingly from primary cohort B cells, while later induction of new antibody responses from naive B cells is strongly suppressed. Such 'primary addiction' decreases sharply as a function of antigenic distance, allowing reimmunization with divergent viral glycoproteins to produce de novo antibody responses targeting epitopes that are absent from the priming variant. Our findings have implications for the understanding of OAS and for the design and testing of vaccines against evolving pathogens.

Infectivity and transmissibility of an avian H3N1 influenza virus in pigs.

In 2019 a low pathogenic H3N1 avian influenza virus (AIV) caused an outbreak in Belgian poultry farms, characterized by an unusually high mortality in chickens. Influenza A viruses of the H1 and H3 subtype can infect pigs and become established in swine populations. Therefore, the H3N1 epizootic raised concern about AIV transmission to pigs and from pigs to humans. Here, we assessed the replication efficiency of this virus in explants of the porcine respiratory tract and in pigs, using virus titration and/or RT-qPCR. We also examined transmission from directly, intranasally inoculated pigs to contact pigs. The H3N1 AIV replicated to moderate titers in explants of the bronchioles and lungs, but not in the nasal mucosa or trachea. In the pig infection study, infectious virus was only detected in a few lung samples collected between 1 and 3 days post-inoculation. Virus titers were between 1.7 and 4.8 log10 TCID50. In line with the ex vivo experiment, no virus was isolated from the upper respiratory tract of pigs. In the transmission experiment, we could not detect virus transmission from directly inoculated to contact pigs. An increase in serum antibody titers was observed only in the inoculated pigs. We conclude that the porcine respiratory tract tissue explants can be a useful tool to assess the replication efficiency of AIVs in pigs. The H3N1 AIV examined here is unlikely to pose a risk to swine populations. However, continuous risk assessment studies of emerging AIVs in pigs are necessary, since different virus strains will have different genotypic and phenotypic traits.

Coagulopathy and the humoral response against viral proteins in patients at different stages of COVID-19.

BACKGROUND: Patients with severe coronavirus disease 2019 (COVID-19) often present with coagulopathies and have high titres of circulating antibodies against viral proteins. OBJECTIVES: Herein, we evaluated the association between D-dimer and circulating immunoglobulin levels against viral proteins in patients at different clinical stages of COVID-19. METHODS: For this, we performed a cross-sectional study involving patients of the first wave of COVID-19 clinically classified as oligosymptomatic (n = 22), severe (n = 30), cured (n = 27) and non-infected (n = 9). Next, we measured in the plasma samples the total and fraction of immunoglobulins against the nucleoprotein (NP) and the receptor-binding domain (RBD) of the spike proteins by enzyme-linked immunosorbent assay (ELISA) assays. FINDINGS: Patients with severe disease had a coagulation disorder with high levels of D-dimer as well as circulating IgG against the NP but not the RBD compared to other groups of patients. In addition, high levels of D-dimer and IgG against the NP and RBD were associated with disease severity among the patients in this study. MAIN CONCLUSIONS: Our data suggest that IgG against NP and RBD participates in the worsening of COVID-19. Although the humoral response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is partially understood, and more efforts are needed to clarify gaps in the knowledge of this process.

Relationship between Anti-SARS-CoV-2 S Abs and IFN-λ3 Levels in the Administration of Oxygen following COVID-19 Vaccination.

Although the effectiveness of vaccination at preventing hospitalization and severe coronavirus disease (COVID-19) has been reported in numerous studies, the detailed mechanism of innate immunity occurring in host cells by breakthrough infection is unclear. One hundred forty-six patients were included in this study. To determine the effects of vaccination and past infection on innate immunity following SARS-CoV-2 infection, we analyzed the relationship between anti-SARS-CoV-2 S Abs and biomarkers associated with the deterioration of COVID-19 (IFN-λ3, C-reactive protein, lactate dehydrogenase, ferritin, procalcitonin, and D-dimer). Anti-S Abs were classified into two groups according to titer: high titer (≥250 U/ml) and low titer (<250 U/ml). A negative correlation was observed between anti-SARS-CoV-2 S Abs and IFN-λ3 levels (r = -0.437, p < 0.001). A low titer of anti-SARS-CoV-2 S Abs showed a significant association with oxygen demand in patients, excluding aspiration pneumonia. Finally, in a multivariate analysis, a low titer of anti-SARS-CoV-2 S Abs was an independent risk factor for oxygen demand, even after adjusting for age, sex, body mass index, aspiration pneumonia, and IFN-λ3 levels. In summary, measuring anti-SARS-CoV-2 S Abs and IFN-λ3 may have clinical significance for patients with COVID-19. To predict the oxygen demand of patients with COVID-19 after hospitalization, it is important to evaluate the computed tomography findings to determine whether the pneumonia is the result of COVID-19 or aspiration pneumonia.

Depressive symptoms predict antibody titers after a second dose of the SARS-CoV-2 BNT162b2 vaccine among hospital workers in Japan.

BACKGROUND: Although factors associated with the antibody response to the BNT162b2 mRNA COVID-19 vaccine have been reported, psychological factors have not been examined. Depression or anxiety may affect vaccine reactions because these factors influence immune responses. This study aimed to determine whether psychological status at the time of vaccination predicts antibody responses. METHODS: A prospective observational study of the BNT162b2 mRNA COVID-19 vaccine response was carried out among individuals attending for an annual health check-up. Participants included 78 volunteers out of 80 hospital workers in Nagoya, Japan. No participants had been infected with COVID-19 and all gave written informed consent to participate in the study. Blood samples were obtained approximately 28 days after the second dose of the vaccine, and antibody titers of the SARS-CoV-2 spike protein were determined using the SARS-CoV-2 IgG II Quant assay. Participants completed the Japanese version of the hospital anxiety and depression scale (HADS) questionnaire, one day before both vaccinations. Participants also recorded any adverse reactions, such as body temperature and other side effects, every day for two weeks after each dose. The relationships between antibody titers and the predictive factors were analyzed using multiple linear regression analysis, with the antibody titers as the dependent variables, followed by univariate analysis. RESULTS: Multiple linear regression analysis revealed that no or excessive alcohol intake (p = 0.039), poor results from a health check-up (p = 0.011), a longer duration between the second dose and blood collection (p = 0.039), and increased degree of depressive symptoms (p = 0.041) were significant negative predictors of antibody titers, while body temperature one day after the second dose as a significant positive predictor of antibody titers (p < 0.0005). CONCLUSION: We identified that depressive symptoms just before the second dose of the BNT162b2 mRNA COVID-19 were an independent negative predictor of antibody responses, in addition to other factors. Our results highlight the importance of mental health at the time of vaccination to achieve the higher antibody responses necessary to acquire humoral immunity.

Cellular and humoral immune response to the fourth Pfizer-BioNTech COVID-19 vaccine dose in individuals aged 60 years and older.

With the emergence of the severe acute respiratory syndrome 2 (SARS-CoV-2) B.1.1.529/BA.1 (Omicron) variant in early 2022, Israel began vaccinating individuals 6o years of age or older with a fourth BNT162b2 vaccine. While the decision was based on little experimental data, longer follow-up showed clinical effectiveness of the fourth dose with reduction in the number of severely affected individuals. However, the immune response to fourth vaccine dose in this age group was not yet characterized, and little is known about the immunogenicity of repeated vaccine dosing in this age group. We therefore aimed to evaluate the humoral and cellular immune response pre- and 3-week post- the fourth vaccine dose in patients age 60 years or older. For this purpose, blood samples were collected from donors age 60 years or older, all received their 3rd vaccine dose 5 months prior. Serum samples were evaluated for the presence of anti-Spike protein (anti-S) antibodies (N = 133), and peripheral blood mononuclear cells (PBMCs) were evaluated by flow cytometry for their ability to respond to the SARS-CoV-2 wild type Spike-glycoprotein peptide mix, Membrane-glycoprotein (M) peptide mix and to the mutated Spike-regions of the Omicron variant (N = 34). Three weeks after the fourth vaccine dose, 24 out of 34 donors (70.5%) showed significant increase in the number of cells responding to the wild type S-peptide mix. Of note, out of 34 donors, 11 donors (32.3%) had pre-boost anti-M T-cell response, none of which had history of confirmed COVID-19, suggesting possible asymptomatic exposure. Interestingly, in M non-responding individuals, no statistically significant increase in the cellular response was observed following stimulation with omicron S-mutated regions. While there are limited data regarding the longevity of the observed response, our results are in accordance with the described clinical efficacy, provide mechanistic evidence to support it and argue against vaccine-induced or age-related immunosenescence.

Quantitative Antibody Levels Against SARS-CoV-2 Spike Protein in COVID-19 and Multisystem Inflammatory Syndrome in Children.

The majority of children with coronavirus diseases 2019 (COVID-19) are asymptomatic or develop mild symptoms, and a small number of patients require hospitalization. Multisystem inflammatory syndrome in children (MIS-C) is one of the most severe clinical courses of COVID-19 and is suggested to be a hyperinflammatory condition. This study aimed to compare quantitative antibody levels against SARS-CoV-2 spike protein in children with COVID-19 and MIS-C. Blood samples from 75 patients [n = 36 (48%) with mild/asymptomatic (group 1), n = 22 (29.3%) with moderate-to-severe SARS-CoV-2 infection (group 2) and n = 17 (22.6%) patients with MIS-C (group 3)] were analyzed 3 months after COVID-19. The majority of the children with asymptomatic/mild COVID-19 symptoms (80.6%), moderate/severe disease (90.9%), and MIS-C (82.4%) had detectable IgG antibodies to SARS-CoV-2 spike protein (p = 0.567). The mean antibody value against SARS-CoV-2 spike protein was 321.9 ± 411.6 in group 1, 274 ± 261 in group 2, and 220 ± 299 in group 3, respectively (p > 0.05). Patients diagnosed with COVID-19 (asymptomatic/mild+moderate/severe) and those with MIS-C were also compared; the antibody positivity rates [COVID-19 group: 85.5%, MIS-C group: 82.4%, (p = 0.833)] and mean antibody values [COVID-19 group: 303.9 ± 360.3, MIS-C group: 220 ± 299, (p > 0.05)] were similar in both groups. In conclusion, the majority of children with COVID-19 and MIS-C developed a detectable antibody level against SARS-CoV-2 spike protein 3 months after COVID-19. Quantitative antibody levels were similar in both asymptomatic/mild disease, moderate/severe disease, and MIS-C group. Long-term studies evaluating antibody responses in children with COVID-19 and MIS-C are needed for more accurate vaccine schedules.

Humoral and cellular immune response and the safety of third SARS-CoV-2 mRNA vaccine with longer interval after the second vaccination in kidney transplant recipients.

We evaluated the humoral and cellular immune responses and safety of the third severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine with a longer interval after the second vaccination in kidney transplant recipients (KTRs). We enrolled 54 kidney transplant recipients without a history of coronavirus disease 2019 (COVID-19), who received a third dose of the vaccine. We assessed anti-SARS-CoV-2 spike antibody and antigen-specific T cells using enzyme-linked immunospot (ELISpot) against the spike protein at baseline, after the second vaccination, and after the third vaccination. We also evaluated the adverse events related to each dose of the vaccine. The duration between the second and third vaccinations was 7 ± 1 month. All 17 (100%) KTRs with anti-SARS-CoV-2 antibody positivity after the second vaccination and 27 of 37 (73%) KTRs without anti-SARS-CoV-2 antibody positivity after the second vaccination were positive for anti-SARS-CoV-2 antibodies (p=0.022). Anti-SARS-CoV-2 antibody titers were significantly higher than those after the second vaccination (p<0.001). Age ≥ 60 years and lymphocyte count < 1150/mm3 were confirmed as risk factors for anti-SARS-CoV-2 antibody negativity after the third vaccination in multivariate regression analysis. ELISpot cytokine activities were positive after the third vaccination in 26 of 29 (90%) KTRs with ELISpot cytokine activity positivity after the second vaccination and 12 of 24 (50%) KTRs without ELISpot cytokine activity after the second vaccination. The rate of change in cytokine activity after the third vaccination was significantly higher than that after the second vaccination (p<0.001). Only lymphocyte counts less than 1150/mm3 were confirmed as risk factors for ELISpot cytokine activity negativity in the multivariate regression analysis. Systemic adverse events classified as greater than moderate did not differ for each vaccine dose. None of the patients showed clinical symptoms of acute rejection. The third SARS-CoV-2 mRNA vaccine administration, with a longer interval after the second vaccination, improved humoral and cellular immune responses to SARS-CoV-2 mRNA vaccines without severe adverse effects in the KTRs.

Dynamic changes in peripheral lymphocytes and antibody response following a third dose of SARS-CoV-2 mRNA-BNT162b2 vaccine in cancer patients.

The aim of this study was to evaluate the association of circulating lymphocytes profiling with antibody response in cancer patients receiving the third dose of COVID-19 mRNA-BNT162b2 vaccine. Immunophenotyping of peripheral blood was used to determine absolute counts of lymphocyte subsets, alongside detection of IgG antibodies against receptor-binding-domain (RBD) of the SARS-CoV-2 Spike protein (S1) before booster dosing (timepoint-1) and four weeks afterward (timepoint-2). An IgG titer ≥ 50 AU/mL defined a positive seroconversion response. An IgG titer ≥ 4446 AU/mL was assumed as a correlate of 50% vaccine efficacy against symptomatic infections. A total of 258 patients on active treatment within the previous six months were enrolled between September 23 and October 7, 2021. The third dose resulted in an exponential increase in median anti-RBD-S1 IgG titer (P < 0.001), seroconversion rates (P < 0.001), and 50% vaccine efficacy rates (P < 0.001). According to ROC curve analysis, T helper and B cells were significantly associated with seroconversion responses at timepoint-1, whereas only B cells were relevant to 50% vaccine efficacy rates at timepoint-2. A positive linear correlation was shown between anti-RBD-S1 IgG titers and these lymphocyte subset counts. Multivariate analysis ruled out a potential role of T helper cells but confirmed a significant interaction between higher B cell levels and improved antibody response. These findings suggest that peripheral counts of B cells correlate with humoral response to the third dose of mRNA-BNT162b2 vaccine in actively treated cancer patients and could provide insights into a more comprehensive assessment of vaccination efficacy.

Seroprevalence of SARS-CoV-2 antibodies among children and adolescents recruited in a malariometric survey in north-eastern Tanzania July 2021.

BACKGROUND: African countries stand out globally as the region seemingly least affected by the COVID-19 pandemic, caused by the virus SARS-CoV-2. Besides a younger population and potential pre-existing immunity to a SARS-CoV-2-like virus, it has been hypothesized that co-infection or recent history of Plasmodium falciparum malaria may be protective of COVID-19 severity and mortality. The number of COVID-19 cases and deaths, however, may be vastly undercounted. Very little is known about the extent to which the Tanzanian population has been exposed to SARS-CoV-2. Here, we investigated the seroprevalence of IgG to SARS-CoV-2 spike protein in two Tanzanian rural communities 1½ years into the pandemic and the association of coinciding malaria infection and exposure. METHODS: During a malariometric survey in July 2021 in two villages in north-eastern Tanzania, blood samples were taken from 501 participants (0-19 years old). Malaria was detected by mRDT and microscopy. Levels of IgG against the spike protein of SARS-CoV-2 were measured by ELISA as well as IgG against five different antigens of P. falciparum; CIDRα1.1, CIDRα1.4 and CIDRα1.5 of PfEMP1 and GLURP and MSP3. RESULTS: The seroprevalence of SARS-CoV-2 IgG was 39.7% (106/267) in Kwamasimba and 32.5% (76/234) in Mkokola. In both villages the odds of being seropositive increased significantly with age (AOR = 1.12, 95% CI 1.07-1.17, p < 0.001). P. falciparum malaria prevalence by blood smear microscopy was 7.9% in Kwamasimba and 2.1% in Mkokola. 81.3% and 70.5% in Kwamasimba and Mkokola, respectively, showed recognition of minimum one malaria antigen. Residing in Kwamasimba was associated with a broader recognition (AOR = 1.91, 95% CI 1.34-2.71, p < 0.001). The recognition of malaria antigens increased significantly with age in both villages (AOR = 1.12; 95% CI 1.08-1.16, p < 0.001). Being SARS-CoV-2 seropositive did not associate with the breadth of malaria antigen recognition when adjusting for age (AOR = 0.99; 95% CI 0.83-1.18; p = 0.91). CONCLUSION: More than a third of the children and adolescents in two rural communities in Tanzania had antibodies to SARS-CoV-2. In particular, the adolescents were seropositive but being seropositive did not associate with the status of coinciding malaria infections or previous exposure. In Tanzania, natural immunity may have developed fast, potentially protecting a substantial part of the population from later variants.

Long-term antibody production and viremia in American mink (Neovison vison) challenged with Aleutian mink disease virus.

BACKGROUND: Selecting American mink (Neovison vison) for tolerance to Aleutian mink disease virus (AMDV) has gained popularity in recent years, but data on the outcomes of this activity are scant. The objectives of this study were to determine the long-term changes in viremia, seroconversion and survival in infected mink. Mink were inoculated intranasally with a local isolate of Aleutian mink disease virus (AMDV) over 4 years (n = 1742). The animals had been selected for tolerance to AMDV for more than 20 years (TG100) or were from herds free of AMDV (TG0). The progenies of TG100 and TG0, and their crosses with 25, 50 and 75% tolerance ancestry were also used. Blood samples were collected from each mink up to 14 times until 1211 days post-inoculation (dpi) and were tested for viremia by PCR and for anti-AMDV antibodies by counter-immunoelectrophoresis (CIEP). Viremia and CIEP status were not considered when selecting replacements. Low-performing animals were pelted and the presence of antibodies in their blood and antibody titer were measured by CIEP, and viremia and viral DNA in seven organs (n = 936) were tested by PCR. RESULTS: The peak incidences of viremia (66.7%) and seropositivity (93.5%) were at 35 dpi. The incidence of viremia decreased over time while the incidence of seroconversion increased. The least-squares means of the incidence of PCR positive of lymph node (0.743) and spleen (0.656) were significantly greater than those of bone marrow, liver, kidneys, lungs and small intestine (0.194 to 0.342). Differences in tolerant ancestry were significant for every trait measured. Incidences of viremia over time, terminal viremia, seropositivity over time, AMDV DNA in organs and antibody titer were highest in the susceptible groups (TG0 or TG25) and lowest in the tolerant groups (TG100 or TG75). CONCLUSION: Previous history of selection for tolerance resulted in mink with reduced viral replication and antibody titer. Viremia had a negative effect and antibody production had a positive effect on survival and productivity.