Viruses-Basel最新文献

Background: The COVID-19 pandemic significantly altered the circulation of respiratory viruses, including influenza. This study aimed to compare the epidemiology and clinical characteristics of paediatric influenza before, during, and after the pandemic.

Methods: We retrospectively analysed 553 children aged 0-18 years hospitalised with laboratory-confirmed influenza at a paediatric infectious disease centre in Bydgoszcz, Poland, between September 2017 and August 2025. Patients were stratified into pre-pandemic (A), pandemic (B), and post-pandemic (C) periods. Epidemiological indicators, influenza type, age, sex, and hospital stay duration were assessed using χ² and non-parametric tests.

Results: Hospitalisations varied across seasons, lowest in 2021/22 (n = 18) and highest in 2024/25 (n = 175). Seasonal peaks occurred January-March in groups A and C, whereas group B showed a bimodal pattern in December and March-April. Influenza type A predominated in all periods, though less during the pandemic (56.7% vs. 89.2% pre-pandemic and 73.2% post-pandemic). Median hospital stay decreased from 5 days pre-pandemic to 4 days during and after the pandemic. None of the hospitalised children were vaccinated.

Conclusions: The COVID-19 pandemic influenced influenza seasonality, virus type distribution, and hospitalisation patterns in children. Observed shifts highlight the importance of ongoing surveillance and targeted vaccination strategies to mitigate influenza burden in the post-pandemic period.

It is with profound sadness and a deep sense of loss that we mourn the passing of Professor Andrew Otis Jackson on 6 July 2025 [...].

Varicella-zoster virus (VZV) is a human neurotropic herpesvirus. The primary infection with VZV causes chickenpox and establishes latency in sensory and dorsal root ganglia. Viral reactivation leads to herpes zoster (HZ), which is accompanied by complications such as postherpetic neuralgia (PHN), causing a significant disease burden. At present, vaccination is the most effective preventive measure. We developed a recombinant zoster vaccine, gE/BFA01, which comprises truncated VZV glycoprotein E and the liposome-based adjuvant BFA01 (containing MPL and QS-21). In this study, we evaluated the recombinant zoster vaccine's immunogenicity in a live attenuated VZV-primed C57BL/6N mouse model and explored the mechanism of action of the BFA01 adjuvant. The results indicate that the gE/BFA01 vaccine induces superior antibody responses and stronger cellular immune responses compared with gE with aluminum hydroxide. Furthermore, gE/BFA01 showed comparable immunogenicity to the licensed vaccine Shingrix. Mechanistic investigations revealed that the BFA01 adjuvant can enhance the recruitment of innate immune cells at the injection site, increase the expression of DCs surface maturation markers, and activate multiple inflammatory signaling pathways in lymph nodes. Collectively, these findings indicate that gE/BFA01 can induce potent humoral and cellular responses, supporting its further development as a high-efficiency vaccine candidate.

Background: Respiratory syncytial virus (RSV) is one of the leading causes of lower respiratory tract illness and hospitalizations in children aged ≤5 years worldwide. The aim of this study was to characterize the Polish population of patients aged ≤5 years who were hospitalized due to RSV infection, focusing on their clinical and epidemiological characteristics as well as treatment patterns.

Methods: This retrospective observational study was conducted between November 2023 and February 2024 in 41 hospitals with pediatric departments across Poland. Data from patients aged ≤5 years admitted due to RSV infection confirmed with antigen test or RT-PCR were collected. The dataset was weighted and extrapolated to allow conclusions applicable to the general population of patients aged 0-5 years hospitalized with RSV infection in Poland.

Results: Data from 419 patients were analyzed. Over half (57.4%) were younger than 12 months, 84% were born at term, and 85.8% had no comorbidities. The most frequent manifestations of RSV infections were pneumonia (56.8%), bronchiolitis (35.9%), and bronchitis (12.4%). Viral co-infections were identified in 8% of patients. Regarding treatment, 21.1% of patients required respiratory support, 67.6% received inhaled steroid therapy, 61.5% were treated with antibiotics, 48.1% received beta2-mimetics and anticholinergics, and 44.3% underwent systemic steroid therapy.

Conclusions: Our findings confirm that severe RSV primarily affects the youngest children with no comorbidities who do not present high risk conditions. To reduce the overall disease burden, preventive strategies should be offered to all children, not being limited to those in risk groups.

The global distribution of HIV-1 subtypes exhibits significant regional variations, with evolving epidemiological patterns over time. China currently experiences concurrent circulation of multiple HIV-1 subtypes, and the transmission landscape is becoming increasingly complex and diversified. We performed prospective molecular surveillance and drug-resistance profiling of HIV-1 in Wuhan City to delineate the local genotypic structure and to guide antiretroviral therapy. A total of 149 whole blood samples from HIV-1-infected individuals preserved in 2022 at a hospital in Wuhan were selected. Peripheral-blood mononuclear cells (PBMCs) were isolated, total RNA extracted, and the Gag, Pol, and Env regions were amplified by nested RT-PCR and sequenced. The sequencing and phylogenetic tree results revealed that subtype B constituted the predominant clade (73/149, 49.1%), followed by CRF07_BC (20, 13.4%), CRF01_AE (13, 8.7%), CRF55_01B (2, 1.3%), and subtype C (1, 0.7%). Drug resistance mutations were detected in 36 cases, involving 41 mutation sites across 21 distinct types. Resistance profiles included two protease inhibitor-associated mutation sites (2 types), seven nucleoside reverse transcriptase inhibitor (NRTI)-related mutation sites (6 types), and 32 non-nucleoside reverse transcriptase inhibitor (NNRTI)-associated mutation sites (13 types).

Human T-lymphotropic virus type 1 (HTLV-1), the first human retrovirus identified, is linked to adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. However, its post-transcriptional regulation remains poorly understood. Here, we used Oxford Nanopore direct RNA sequencing to profile the HTLV-1 transcriptome and epitranscriptome in MT2 cells. We identified 23 transcript isoforms, encompassing canonical and novel splice variants. Polyadenylation analysis revealed a predominant poly(A) tail length of around 50-100 nucleotides with transcript-specific variations. Distinct RNA modifications, including pseudouridine, N⁶-methyladenosine, and 5-methylcytidine, were enriched near the 3' end and varied among transcript classes, with generally lower modification ratios in viral transcripts. These findings provide a more comprehensive map of HTLV-1 RNA splicing, polyadenylation, and modifications in MT2 cells, offering new insights into viral gene regulation and pathogenic mechanisms.

Avian influenza viruses (AIVs), including H5N1 and H7N9, from the Orthomyxoviridae family present substantial public health concerns. The predominant circulating clade 2.3.4.4b has demonstrated enhanced capacity for mammalian adaptation, raising concerns about potential reassortment with human seasonal influenza viruses. Unlike H7N9's limited host range, H5N1 infects birds, various mammals, and humans. Recent concerns include widespread H5N1 infection of U.S. dairy cattle across 18 states, affecting over 1000 herds with 71 human infections (70 H5N1 and 1 H5N5). Key observations include cow-to-cow transmission, viral presence in milk, and transmission to humans, mainly through occupational exposure. Evidence of mammal-to-mammal transmission has been documented in European and Canadian foxes and South American marine mammals. Standard pasteurization effectively inactivates the virus in milk. The continuing mammalian adaptations, particularly mutations like PB2-E627K, PB2-D701N, and PB2-M535I, suggest potential for further evolution in new hosts, emphasizing the need for enhanced surveillance to mitigate pandemic risks.

Severe dengue virus (DENV) infections are associated with circulating non-neutralizing antibodies generated during heterotypic infections. Although antibodies are key mediators of both protection and pathogenesis, the specific dynamics of B cells (Bc) and their antibody responses remain insufficiently characterized due to limited methods of identifying DENV-specific Bc (DENV-Bc) and the absence of animal models resembling the human disease. Here, we developed a spectral flow cytometry assay employing biotinylated virus-like particles (VLPs) to detect DENV-Bc in C57BL/6 mice and children hospitalized with dengue. DENV-1 and DENV-2 VLPs were biotinylated, and the efficiency of biotin incorporation was assessed with an HABA-avidin assay and ELISA. Serotype specificity and optimal binding conditions were confirmed using hybridomas 4G2 (pan-flavivirus) and 3H5-1 (DENV-2 specific). Fluorescent agglutimers were subsequently generated by coupling biotinylated VLPs to streptavidin-fluorochrome complexes. Splenocytes from intraperitoneally DENV-infected mice and peripheral blood mononuclear cells (PBMCs) from naturally infected pediatric patients were stained with these VLPs and Bc-lineage markers. Biotinylated VLPs bound specifically to hybridomas, and this binding was competitively inhibited by unlabeled VLPs. After secondary DENV challenge, VLPs identified DENV-specific class-switched plasmablasts in mice. Circulating DENV-specific plasmablasts were also detected in children, with agglutimers enabling the discrimination of serotype-specific and cross-reactive responses in primary and secondary infections. This VLP-based approach represents a scalable platform to investigate the protective and pathogenic roles of DENV-Bc in infection and vaccination.

Emerging and re-emerging viruses continue to pose major threats to public health. Their ability to adapt, cross species barriers, and spread rapidly can trigger severe outbreaks or even pandemics. Strengthening preparedness with comprehensive and efficient strategies is therefore essential. Here, we explore the key components of viral outbreak preparedness, including surveillance systems, diagnostic capacity, prevention and control measures, non-pharmaceutical interventions, antiviral therapeutics, and research and development. We emphasize the increasing importance of genomic surveillance, wastewater-based surveillance, real-time data sharing, and the One Health approach to better anticipate zoonotic spillovers. Current challenges and future directions are also discussed. Effective preparedness requires transparent risk communication and equitable access to diagnostics, vaccines, and therapeutics. The COVID-19 pandemic highlighted both the promise of next-generation vaccine platforms and the necessity of maintaining diagnostic capacity, as early testing delays hindered containment efforts. Countries adopted various non-pharmaceutical interventions: risk communication and social distancing proved to be the most effective, while combined workplace infection-prevention measures outperformed single strategies. These experiences highlight the importance of early detection, rapid response, and multisectoral collaboration in mitigating the impact of viral outbreaks. By applying best practices and lessons learned from recent events, global health systems can strengthen resilience and improve readiness for future viral threats.

The natural ability of certain bacterial species to form biofilms presents numerous challenges for modern medicine and the food and pharmaceutical industries [...].