Immune Response to SARS-CoV-2 XBB.1.5 and JN.1 Variants Following XBB.1.5 Booster Vaccination in Liver Transplant Recipients.

Background/objectives: The efficacy of monovalent BNT162b2 Omicron XBB.1.5 booster vaccination in liver transplant recipients (LTRs) has yet to be described, particularly regarding the immune response to emerging variants like JN.

MVA-based SARS-CoV-2 vaccine candidates encoding different spike protein conformations induce distinct early transcriptional responses which may impact subsequent adaptive immunity.

Introduction: Vaccine platforms such as viral vectors and mRNA can accelerate vaccine development in response to newly emerging pathogens, as demonstrated during the COVID-19 pandemic. However, the differential effects of platform and antigen insert on vaccine immunogenicity remain incompletely understood. Innate immune responses induced by viral vector vaccines are suggested to have an adjuvant effect for subsequent adaptive immunity.

Dissecting humoral immune responses to an MVA-vectored MERS-CoV vaccine in humans using a systems serology approach.

Besides neutralizing antibodies, which are considered an important measure for vaccine immunogenicity, Fc-mediated antibody functions can contribute to antibody-mediated protection. They are strongly influenced by structural antibody properties such as subclass and Fc glycan composition. We here applied a systems serology approach to dissect humoral immune responses induced by MVA-MERS-S, an MVA-vectored vaccine against the Middle East respiratory syndrome coronavirus (MERS-CoV).

Delayed Induction of Noninflammatory SARS-CoV-2 Spike-Specific IgG4 Antibodies Detected 1 Year After BNT162b2 Vaccination in Children.

Humoral immune responses after BNT162b2 vaccination are predominantly composed of immunoglobulin (Ig) G1 and IgG3 subclass antibodies. As previously described in adults, S1-specific and receptor-binding domain-specific IgG4 levels increase significantly 1 year after the second BNT162b2 vaccination in children 5-11 years of age. Understanding mRNA vaccine-specific IgG4 responses in all age groups is crucial as more mRNA vaccines will reach licensure in the coming years.

Lack of evidence of acute HEV infections as a sexually transmitted disease: Data from a German cohort of PrEP users.

Background: While the sexual transmissibility of HAV in MSM has been extensively described, the potential for sexual transmission of HEV has not been definitively established. Although HEV has been detected in the ejaculate of chronically infected men, studies among MSM PrEP users in France did not observe an elevated anti-HEV seroprevalence as an indicator of increased exposure risk by sexual intercourse.

Patients And Methods: A total of 111 unselected PrEP users and 111 age- and sex-matched blood donors were tested for anti-HEV IgG, IgM and HEV (PCR).

SARS-CoV-2 vaccination may mitigate dysregulation of IL-1/IL-18 and gastrointestinal symptoms of the post-COVID-19 condition.

The rapid development of safe and effective vaccines helped to prevent severe disease courses after SARS-CoV-2 infection and to mitigate the progression of the COVID-19 pandemic. While there is evidence that vaccination may reduce the risk of developing post-COVID-19 conditions (PCC), this effect may depend on the viral variant. Therapeutic effects of post-infection vaccination have been discussed but the data for individuals with PCC remains inconclusive.

Hybrid immunity to SARS-CoV-2 in patients with chronic lymphocytic leukemia.

Objective: Preventing severe COVID-19 remains a priority globally, particularly in the immunocompromised population. As shown in healthy individuals, immunity against SARS-CoV-2 can be yielded by previous infection, vaccination, or both (hybrid immunity). The objective of this observation study was to investigate hybrid immunity in patients with chronic lymphocytic leukemia (CLL).

MVA-based vaccine candidates encoding the native or prefusion-stabilized SARS-CoV-2 spike reveal differential immunogenicity in humans.

In response to the COVID-19 pandemic, multiple vaccines were developed using platforms such as viral vectors and mRNA technology. Here, we report humoral and cellular immunogenicity data from human phase 1 clinical trials investigating two recombinant Modified Vaccinia virus Ankara vaccine candidates, MVA-SARS-2-S and MVA-SARS-2-ST, encoding the native and the prefusion-stabilized SARS-CoV-2 spike protein, respectively. MVA-SARS-2-ST was more immunogenic than MVA-SARS-2-S, but both were less immunogenic compared to licensed mRNA- and ChAd-based vaccines in SARS-CoV-2 naïve individuals.

Identification of a Spike-Specific CD8+ T-Cell Epitope Following Vaccination Against the Middle East Respiratory Syndrome Coronavirus in Humans.

Licensed vaccines against the Middle East respiratory syndrome coronavirus (MERS-CoV), an emerging pathogen of concern, are lacking. The modified vaccinia virus Ankara vector-based vaccine MVA-MERS-S, expressing the MERS-CoV-spike glycoprotein (MERS-S), is one of 3 candidate vaccines in clinical development and elicits robust humoral and cellular immunity. Here, we identified for the first time a MERS-S-specific CD8+ T-cell epitope in an HLA-A*03:01/HLA-B*35:01-positive vaccinee using a screening assay, intracellular cytokine staining, and in silico epitope prediction.

Systems biology analysis reveals distinct molecular signatures associated with immune responsiveness to the BNT162b COVID-19 vaccine.

Background: Human immune responses to COVID-19 vaccines display a large heterogeneity of induced immunity and the underlying immune mechanisms for this remain largely unknown.

Methods: Using a systems biology approach, we longitudinally profiled a unique cohort of female high and low responders to the BNT162b vaccine, who were known from previous COVID-19 vaccinations to develop maximum and minimum immune responses to the vaccine. We utilized high dimensional flow cytometry, bulk and single cell mRNA sequencing and 48-plex serum cytokine analyses.

RSV vaccination strategies for high-risk patients 2023: a collaborative position paper by leading German medical societies and organizations.

Respiratory syncytial virus (RSV) inflicts severe illness and courses of infections not only in neonates, infants, and young children, but also causes significant morbidity and mortality in older adults and in people with immunosuppression, hemato-oncologic disease, chronic lung disease, or cardiovascular disease. In June and August 2023, effective vaccines against RSV were approved for the first time by the European Medicines Agency (EMA) for the EU. The respective pivotal studies showed a very high efficacy of the vaccine in preventing severe RSV-associated respiratory infections.

Comparative analysis of characteristics and outcomes in hospitalized COVID-19 patients infected with different SARS-CoV-2 variants between January 2020 and April 2022 - A retrospective single-center cohort study.

Background: Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, the roll-out of vaccines and therapeutic agents, as well as the emergence of novel SARS-CoV-2 variants, have shown significant effects on disease severity.

Methods: Patients hospitalized at our center between January 2020 and April 2022 were attributed to subgroups depending on which SARS-CoV-2 variant was predominantly circulating in Germany: (i) Wild-type: January 1, 2020, to March 7, 2021, (ii) Alpha variant: August 3, 2021, to June 27, 2021, (iii) Delta variant: June 28, 2021, to December 26, 2021, and (iv) Omicron variant: December 27, 2021, to April 30, 2022.

Results: Between January 2020 and April 2022, 1500 patients with SARS-CoV-2 infections were admitted to the University Medical Center Hamburg-Eppendorf.

Vagus nerve inflammation contributes to dysautonomia in COVID-19.

Dysautonomia has substantially impacted acute COVID-19 severity as well as symptom burden after recovery from COVID-19 (long COVID), yet the underlying causes remain unknown. Here, we hypothesized that vagus nerves are affected in COVID-19 which might contribute to autonomic dysfunction. We performed a histopathological characterization of postmortem vagus nerves from COVID-19 patients and controls, and detected SARS-CoV-2 RNA together with inflammatory cell infiltration composed primarily of monocytes.