Influenza poses a significant global health challenge due to its rapid mutation and antigenic variability, which often leads to seasonal epidemics and frequent outbreaks. Traditional vaccines struggle to offer comprehensive protection because of mismatches with circulating viral strains. The development of a broad-spectrum vaccine is therefore crucial. This paper explores the potential of mRNA vaccine technology to address these challenges by providing a swift, adaptable, and broad protective response against evolving influenza strains. We detail the mechanisms of antigenic variation in influenza viruses and discuss the rapid design and production, enhanced immunogenicity, encoding of multiple antigens, and safety and stability of mRNA vaccines compared to traditional methods. By leveraging these advantages, mRNA vaccines represent a revolutionary approach in influenza prevention, potentially offering broad-spectrum protection and significantly improving global influenza management and response strategies.

Background/Objectives: Influenza viruses are highly transmissible and mutable, posing a significant burden on public health. This study aimed to design a recombinant multi-epitope vaccine with broad protective potential. Methods: Immunoinformatic approaches were employed to predict epitopes from over 30,000 protein sequences retrieved from protein databases. Epitopes were filtered using four key indicators: antigenicity, allergenicity, toxicity, and conservancy. Population coverage analysis was conducted to estimate the proportion of the global population that could potentially benefit from the vaccine. Secondary and tertiary structures of the recombinant vaccine were predicted using the PSIPRED server and AlphaFold2. The vaccine efficacy was validated through an immune simulation, molecular docking, and molecular dynamics simulation. Results: A recombinant multi-epitope vaccine demonstrating strong antigenicity, no allergenicity or toxicity, and high conservation across different subtypes was successfully constructed. Population coverage analysis indicated that the vaccine could elicit an immune response in 90.14% of the global population. Both the secondary and tertiary structures of the vaccine were accurately predicted. Molecular dynamics simulations further validated the structural stability and interactions of the vaccine components with TRL4. Molecular docking confirmed the robust binding affinity of T-cell epitopes to MHC molecules. Simulated immunity studies showed that the vaccine induced the proliferation of memory B cells and T cells, enabling rapid antibody production during viral challenges. Conclusions: This study provides a promising basis for the development of a broadly protective influenza vaccine, leveraging cutting-edge immunoinformatics and molecular dynamics simulations to address the global challenge posed by influenza virus variability.

Norovirus is a major etiological agent of nonbacterial gastroenteritis around the world. Due to its in vitro culture complexity, high genome diversity, and the lack of cross-reactive immunity between genogroups, there is an unmet urgent need for polyvalent norovirus vaccines that provide broad-spectrum protection, and no vaccine has gained global approval to date. In this study, we constructed a bivalent norovirus vaccine, based on the highly attenuated poxvirus [strain VG9] vector, expressing the major capsid protein VP1 from genotypes GII.4 and GII.17. VG9-NOR exhibited a comparable replication ability to the authentic virus while preserving good safety. After the intramuscular and intranasal immunization of mice, VG9-NOR induced high IgG- and IgA-binding antibody (Ab) titers against GII.4 and GII.17, increased the secretion of GII.4 and GII.17-specific HGBA-blocking antibodies, and enhanced GII.17-specific mucosal immunity. Furthermore, VG9-NOR also induced a Th1-mediated cellular response. These results demonstrate that the polyvalent poxvirus vector vaccine expressing VP1 variants from different subtypes is able to elicit effective protection. Our study highlights the VG9 vector as a highly promising candidate for the development of polyvalent norovirus vaccines.

Influenza B virus (IBV) is a major pathogen affecting the human respiratory tract. B/Victoria is currently the only prevalent influenza B lineage as B/Yamagata has become increasingly rare. Existing influenza vaccines provide limited protection because of the continuous antigenic drift within hemagglutinin (HA), a key membrane protein within the virion. Therefore, the development of novel pan-IBV vaccines has become an urgent priority. In this study, we formulated a high-frequency prevalent antigen (HFPA)-mRNA vaccine based on 10-year prevalent sequences of HA, neuraminidase, nucleoprotein, and the HA stem. We then assessed the broad-spectrum protective effects of the prevalent antigens. The HFPA vaccine induced more robust humoral immune responses, including higher titers of broad-spectrum neutralizing and neuraminidase-inhibiting antibodies and enhanced antibody-dependent cell-mediated cytotoxicity, than attenuated IBV vaccines. The HFPA vaccine also induced a Th1-biased CD4⁺ T cell response, resulting in complete protection against three different IBV subtypes. These findings provide novel insights into the development of pan-IBV vaccines.

Influenza (flu) is a highly prevalent respiratory illness caused by influenza viruses, representing a significant global health burden due to its substantial morbidity and mortality rate. Vaccination remains the most effective strategy for influenza prevention, and well-characterized animal models of influenza infection serve as essential tools for evaluating vaccine protective efficacy. However, animal models utilizing live influenza virus strains pose significant biosafety concerns, and many such strains are not readily available for research. To address these challenges, we established a novel visual mouse infection model using an HIV-based vector system. This model employs influenza pseudoviruses carrying a luciferase reporter gene, enabling real-time monitoring of viral load and in vivo tracking of viral distribution during infection. Using this infection model, we assessed the in vivo protective efficacy of an influenza vaccine and cross-validated the pseudovirus-based evaluation results against a live virus-infected mouse model. Our study thus establishes a safer and more convenient platform for evaluating influenza vaccine efficacy, including the assessment of broad-spectrum neutralization capacity.

Major outbreaks of severe acute respiratory syndrome (SARS) and coronavirus disease 2019 (COVID-19), together with the continuous risk of zoonotic spillover of animal sarbecoviruses, underscore the urgent need for vaccines that confer broad protection across the sarbecovirus subgenus. Current immunogen selection strategies for pansarbecovirus vaccine development predominantly rely on phylogenetic or spike sequence conservation analyses, which often fail to accurately predict the breadth of cross-neutralization. To overcome this limitation, we systematically evaluated cross-neutralization profiles among 25 representative sarbecoviruses from clades 1 and 3 via guinea pig antisera individually raised against full-length spike proteins in pseudovirus neutralization assays while excluding clade 2 viruses lacking known receptor usage. Neutralization profiling revealed four distinct immunogenic clusters that diverged from traditional phylogenetic relationships. Antisera induced by the palm civet–derived SARS-CoV-1 strain SZ1 broadly neutralized all clade 1a viruses, whereas full coverage of clade 1b viruses required at least two distinct immunogens. Remarkably, sera elicited by multiple clade 1 immunogens also neutralized clade 3 viruses despite no prior exposure to clade 3 antigens. Guided by these findings, we proposed a minimal trivalent immunogen combination—SZ1, SARS-CoV-2, and PCoV-GX—that elicited broad neutralization against both clade 1 and clade 3. This rational approach eliminates the need for additional clade 3–specific antigens and provides a preclinical framework for developing next-generation pansarbecovirus vaccines.