Dysbiosis of gut microbiota in COVID-19 is associated with intestinal DNA phage dynamics of lysogenic and lytic infection.

This study compared intestinal DNA phage dynamics and gut microbiota changes observed at the onset of coronavirus disease 2019 (COVID-19). The study participants included 19 healthy individuals and 19 patients with severe acute respiratory syndrome coronavirus 2 infection. Significant differences were observed in the diversity of the intestinal DNA virome after the onset of COVID-19 compared with that in healthy individuals.

An mRNA vaccine candidate encoding H5HA clade 2.3.4.4b protects mice from clade 2.3.2.1a virus infection.

Highly pathogenic avian influenza (HPAI) H5 viruses from different clades have been circulating globally, threatening wild/domestic birds and mammals. Given frequent spillovers and high mortality among mammals, coupled with our inability to predict which clade of H5 virus has pandemic potential, cross-clade protective HPAI H5 vaccines are urgently needed. Here, we demonstrate the applicability of a lipid nanoparticle-based mRNA vaccine modality to induce cross-protective immunity against lethal HPAI virus infection.

Characterization of Omicron BA.4.6, XBB, and BQ.1.1 subvariants in hamsters.

During the Omicron wave, previous variants such as BA.2, BA.4, and BA.

Seroprevalence of severe acute respiratory syndrome coronavirus 2 N antibodies between December 2021 and march 2023 in Japan.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 in China and rapidly spread worldwide, leading to a pandemic. The threat of SARS-CoV-2 is subsiding as most people have acquired sufficient antibodies through vaccination and/or infection to prevent severe COVID-19. After the emergence of the omicron variants, the seroprevalence of antibodies against the N protein elicited by SARS-CoV-2 infection ranged from 44.

Association of gut microbiota with the pathogenesis of SARS-CoV-2 Infection in people living with HIV.

Background: People living with HIV (PLWH) with chronic inflammation may have an increasing risk for coronavirus disease 2019 (COVID-19) severity; however, the impact of their gut microbiota on COVID-19 is not fully elucidated. Here, we analyzed the temporal changes in the gut microbiota composition of hospitalized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected PLWH (PLWH-CoV) and their correlation with COVID-19 severity.

Result: The 16S rRNA analysis results using stool samples (along the timeline from disease onset) from 12 hospitalized PLWH-CoV, whose median CD4 + T cell count was 671 cells/µl, were compared to those of 19 healthy people and 25 PLWH.

Clinical Efficacy of Imdevimab/Casirivimab for Persistent Omicron SARS-CoV-2 Infection in Patients with Hematological Malignancies.

Objective Prolonged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been reported in immunocompromised patients, as they poorly develop antibodies against SARS-CoV-2. We conducted a clinical trial to determine the efficacy of Imdevimab/Casirivimab (Imde/Casiri), an anti-viral monoclonal antibody (mAb), for prolonged infection at our institution. Methods Nine patients with hematological malignancies (six with malignant lymphoma and three with multiple myeloma) in our institution presented with coronavirus disease 2019 caused by SARS-CoV-2 omicron variants (one, five, and one with BA.

An mRNA vaccine encoding the SARS-CoV-2 receptor-binding domain protects mice from various Omicron variants.

Here, we assessed the efficacy of a lipid nanoparticle-based mRNA vaccine candidate encoding the receptor-binding domain (LNP-mRNA-RBD) in mice. Mice immunized with LNP-mRNA-RBD based on the ancestral strain (ancestral-type LNP-mRNA-RBD) showed similar cellular responses against the ancestral strain and BA.5, but their neutralizing activity against BA.

Cardiomyopathy Does Not Exacerbate the Severity of Pneumonia Caused by a SARS-CoV-2 Delta Variant in the J2N-k Hamster Model.

Cardiovascular disease is one of many risk factors that have been linked to increased severity or mortality in coronavirus disease 2019 (COVID-19) patients; however, the exact role of SARS-CoV-2 in the pathogenesis of cardiac inflammatory injury has not been established. A previous study reported that SARS-CoV-2 causes more severe disease with cardiomyopathy in a J2N-k animal model. Here, we investigated the sensitivity of J2N-k hamsters, as a cardiomyopathy animal model, to a delta strain of SARS-CoV-2 compared to J2N-n control animals.

Antiviral efficacy against and replicative fitness of an XBB.1.9.1 clinical isolate.

The emergence and spread of new SARS-CoV-2 variants with mutations in the spike protein, such as the XBB.1.5 and XBB.

Airway surveillance and lung viral control by memory T cells induced by COVID-19 mRNA vaccine.

Although SARS-CoV-2 evolution seeds a continuous stream of antibody-evasive viral variants, COVID-19 mRNA vaccines provide robust protection against severe disease and hospitalization. Here, we asked whether mRNA vaccine-induced memory T cells limit lung SARS-CoV-2 replication and severe disease. We show that mice and humans receiving booster BioNTech mRNA vaccine developed potent CD8 T cell responses and showed similar kinetics of expansion and contraction of granzyme B/perforin-expressing effector CD8 T cells.

Differences among epitopes recognized by neutralizing antibodies induced by SARS-CoV-2 infection or COVID-19 vaccination.

SARS-CoV-2 has gradually acquired amino acid substitutions in its S protein that reduce the potency of neutralizing antibodies, leading to decreased vaccine efficacy. Here, we attempted to obtain mutant viruses by passaging SARS-CoV-2 in the presence of plasma samples from convalescent patients or vaccinees to determine which amino acid substitutions affect the antigenicity of SARS-CoV-2. Several amino acid substitutions in the S2 region, as well as the N-terminal domain (NTD) and receptor-binding domain (RBD), affected the neutralization potency of plasma samples collected from vaccinees, indicating that amino acid substitutions in the S2 region as well as those in the NTD and RBD affect neutralization by vaccine-induced antibodies.

Research article antibody induction and immune response in nasal cavity by third dose of SARS-CoV-2 mRNA vaccination.

Background: The mucosa serves as the first defence against pathogens and facilitates the surveillance and elimination of symbiotic bacteria by mucosal immunity. Recently, the mRNA vaccine against SARS-CoV-2 has been demonstrated to induce secretory antibodies in the oral and nasal cavities in addition to a systemic immune response. However, the mechanism of induced immune stimulation effect on mucosal immunity and commensal bacteria profile remains unclear.

Transmission and re-infection of Omicron variant XBB.1.5 in hamsters.

Background: Like its predecessors in the XBB family, XBB.1.5 is highly immune evasive from therapeutic monoclonal antibodies and neutralizing antibodies generated by vaccination and/or infection.

Characterization of SARS-CoV-2 Omicron BA.2.75 clinical isolates.

The prevalence of the Omicron subvariant BA.2.75 rapidly increased in India and Nepal during the summer of 2022, and spread globally.

Characterization of Influenza A(H1N1)pdm09 Viruses Isolated in the 2018-2019 and 2019-2020 Influenza Seasons in Japan.

The influenza A(H1N1)pdm09 virus that emerged in 2009 causes seasonal epidemic worldwide. The virus acquired several amino acid substitutions that were responsible for antigenic drift until the 2018-2019 influenza season. Viruses possessing mutations in the NA and PA proteins that cause reduced susceptibility to NA inhibitors and baloxavir marboxil, respectively, have been detected after antiviral treatment, albeit infrequently.

High titers of infectious SARS-CoV-2 in corpses of patients with COVID-19.

Objectives: The prolonged presence of infectious SARS-CoV-2 in deceased patients with COVID-19 has been reported. However, infectious virus titers have not been determined. Such information is important for public health, death investigation, and handling corpses.

SARS-CoV-2 Transmission from Virus-Infected Dead Hamsters.

Although it has been 2.5 years since the coronavirus disease 2019 (COVID-19) pandemic began, the transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a dead infected body remains unclear, and in Japan, bereaved family members are often not allowed to view in person a loved one who has died from COVID-19. In this study, we analyzed the possibility of SARS-CoV-2 transmission from a dead body using a hamster model.