The natural virome and pandemic potential: Disease X

Addressing Vaccine Hesitancy in College Students Post COVID-19 Pandemic: A Systematic Review Using COVID-19 as a Case Study

Background: Resistance to vaccinations continues to pose a considerable challenge to attaining widespread vaccination, especially among the college student demographic, who are pivotal in championing public health initiatives. This systematic review investigates the elements that influence reluctance to receive the COVID-19 vaccine among university students globally. Utilizing the WHO's 3C model, which encompasses confidence, complacency, and convenience, this review seeks to pinpoint the main factors and suggest focused strategies to address them. Methods: Following the PRISMA guidelines, we conducted a systematic search in PubMed, Medline, Web of Science, Scopus, Embase, and Global Health. Eligible studies were cross-sectional, peer-reviewed, and examined COVID-19 vaccine hesitancy among college students. Covidence was used for screening, and data were synthesized narratively using the 3C model. Results: Sixty-seven studies (n = 88,345 participants) from 25 countries were included in this study. Confidence factors were the most influential, with fear of side effects (87.18%) and doubts about efficacy (72.4%) as primary concerns. Complacency factors included a low perceived risk of infection (34.9%) and a preference for alternative preventive measures (52.3%). Convenience barriers involved financial costs (58.1%) and difficulty accessing vaccination centers (40.3%). Subgroup analyses revealed variations by academic discipline and geographic region, with medical students showing hesitancy despite their health knowledge. Conclusions: COVID-19 vaccine hesitancy among college students is primarily driven by safety concerns, misinformation, and accessibility barriers. Addressing hesitancy requires transparent risk communication, policy-driven accessibility improvements, and tailored educational interventions. These findings can inform strategies to enhance vaccine uptake among young adults and contribute to broader efforts in pandemic preparedness.

Natural fatal infection of Tembusu virus in bottlenose dolphins in Thailand

Interspecies transmission of viruses poses significant risks to animal and human health. Tembusu virus (TMUV), an emerging flavivirus, is primarily associated with avian diseases. This study reports the first documented natural infection of TMUV in mammals, specifically zoo dolphins in Thailand, offering insights into its evolution, transmission dynamics, and zoonotic potential. In July 2023, three bottlenose dolphins developed neurological symptoms and died. Postmortem analyses, including histopathology, immunohistochemistry, high-throughput sequencing, and transmission electron microscopy, confirmed TMUV infection. Viral loads were high in brain and lung tissues, followed by kidney and spleen whereas the TMUV antigen was identified in only brain tissue. TMUV was localized in neurons and astroglia cells, and immunohistochemistry revealed CD3-positive T lymphocyte perivascular cuffing in the brain. Phylogenetic analysis placed the dolphin TMUV strains within cluster 3, related to strains found in mosquitoes in China. Retrospective analysis of dolphin samples from 2019 confirmed persistent TMUV circulation. Viral isolation on Vero cells showed characteristic cytopathic effects, and transmission electron microscopy revealed enveloped virions. This study highlights the virus's ability to infect diverse hosts, including mammals. The findings underscore the need for continuous surveillance and a One Health approach to mitigate emerging viral threats.

Vector-Free Deep Tissue Targeting of DNA/RNA Therapeutics via Single Capacitive Discharge Conductivity-Clamped Gene Electrotransfer

Viral vector and lipid nanoparticle based gene delivery have limitations around spatiotemporal control, transgene packaging size, and vector immune reactivity, compromising translation of nucleic acid (NA) therapeutics. In the emerging field of DNA and particularly RNA-based gene therapies, vector-free delivery platforms are identified as a key unmet need. Here, this work addresses these challenges through gene electrotransfer (GET) of "naked" polyanionic DNA/mRNA using a single needle form-factor which supports "electro-lens" based compression of the local electric field, and local control of tissue conductivity, enabling single capacitive discharge minimal charge gene delivery. Proof-of-concept studies for "single capacitive discharge conductivity-clamped gene electrotransfer" (SCD-CC-GET) deep tissue delivery of naked DNA and mRNA in the mouse hindlimb skeletal muscle achieve stable (>18 month) expression of luciferase reporter synthetic DNA, and mRNA encoding the reporter yield rapid onset (<3 h) high transient expression for several weeks. Delivery of DNAs encoding secreted alkaline phosphatase and Cal/09 influenza virus hemagglutinin antigen generate high systemic circulating recombinant protein levels and antibody titres. The findings support adoption of SCD-CC-GET for vaccines and immunotherapies, and extend the utility of this technology to meet the demand for efficient vector-free, precision, deep tissue delivery of NA therapeutics.

The Known and Unknown of Global Tick-Borne Viruses

Ticks are crucial vectors for various pathogens associated with human and animal diseases, including viruses. Nevertheless, significant knowledge gaps prevail in our understanding of tick-borne viruses (TBVs). We here examined existing studies on TBVs, uncovering 870 documented virus species across 28 orders, 55 families, and 66 genera. The discovery history, vector ticks, and hosts of TBVs, as well as the clinical characteristics of TBV-induced diseases, are summarized. In total, 176 tick species from nine tick genera were confirmed as vectors for TBVs. Overall, 105 TBVs were associated with infection or exposure to humans and animals. Of them, at least 40 were identified to cause human or animal diseases. This review addresses the current challenges associated with TBV research, including the lack of knowledge about the identification of novel and emerging TBVs, the spillover potentials from ticks to hosts, and the pathogenicity and infection mechanisms of TBVs. It is expected to provide crucial insights and references for future studies in this field, while specifically focusing on expanding surveys, improving TBV identification and isolation, and enhancing the understanding of TBV-vector-host interactions. All of these findings will facilitate the preparation for preventing and treating diseases caused by emerging and novel TBVs.

Prokaryote- and Eukaryote-Based Expression Systems: Advances in Post-Pandemic Viral Antigen Production for Vaccines

This review addresses the ongoing global challenge posed by emerging and evolving viral diseases, underscoring the need for innovative vaccine development strategies. It focuses on the modern approaches to creating vaccines based on recombinant proteins produced in different expression systems, including bacteria, yeast, plants, insects, and mammals. This review analyses the advantages, limitations, and applications of these expression systems for producing vaccine antigens, as well as strategies for designing safer, more effective, and potentially 'universal' antigens. The review discusses the development of vaccines for a range of viral diseases, excluding SARS-CoV-2, which has already been extensively studied. The authors present these findings with the aim of contributing to ongoing research and advancing the development of antiviral vaccines.