Since the first isolation in 1943, the dengue virus (DENV) has spread throughout the world, but effective antiviral drugs or vaccines are still not available. To provide a more stable reporter DENV for vaccine development and antiviral drug screening, we constructed a reporter DENV containing the NanoLuc reporter gene, which was inserted into the 5′ untranslated region and capsid junction region, enabling rapid virus rescue by in vitro ligation. In addition, we established a live imaging mouse model and found that the reporter virus maintained the neurovirulence of prototype DENV before engineering. DENV-4 exhibited dramatically increased neurovirulence following a glycosylation site-defective mutation in the envelope protein. Significant mice mortality with neurological onset symptoms was observed after intracranial infection of wild-type (WT) mice, thus providing a visualization tool for DENV virulence assessment. Using this model, DENV was detected in the intestinal tissues of WT mice after infection, suggesting that intestinal lymphoid tissues play an essential role in DENV pathogenesis.

Background: There is evidence for the protective effects of antibodies targeting non-structural protein 1 (NS1) of Zika virus (ZIKV); however, effective vaccines against ZIKV remain lacking. Methods: In this study, lipid nanoparticle (LNP)-encapsulated mRNA vaccines were designed based on the envelope domain III (EDIII) and NS1 sequences of the ZIKV FSS13025 strain, while protective efficacy was evaluated in a murine model using a ZIKV isolate obtained from Zhejiang Provincial Center for Disease Control and Prevention (Zhejiang CDC). Results: The vaccines were evaluated for key quality attributes—including particle size, polydispersity index (PDI), and encapsulation efficiency—as well as immunogenicity and protective efficacy. Both monovalent vaccine components exhibited uniform particle sizes (PDI < 0.2) and high encapsulation efficiencies (≥80%) and induced high levels of antigen-specific antibodies in mice in a dose-dependent manner. The EDIII mRNA vaccine elicited moderate ZIKV-neutralizing antibody titers as measured by PRNT₅₀, whereas the NS1 vaccine did not induce detectable neutralizing antibodies. Both bicomponent (EDIII + NS1) mRNA vaccines induced a Th1-biased cellular immune response in mouse splenocytes, with significantly greater IFN-γ production compared with either monovalent vaccine. In viral challenge experiments using 1 × 10⁵ PFU ZIKV (Zhejiang CDC isolate, intraperitoneal), the bicomponent vaccine provided complete protection, with 100% survival across all dose groups. In contrast, the EDIII and NS1 monovalent vaccines showed partial protection: mortality was observed in the 20 μg dose groups and exceeded 50% in the 10 μg dose groups. Conclusions: These results demonstrate that the bicomponent EDIII + NS1 mRNA vaccine combination confers superior protective efficacy compared with either component alone, consistent with a synergistic effect between humoral and cellular immune responses. This study provides a novel strategy for next-generation Zika vaccine development.

Japanese encephalitis virus (JEV) comprises a single serotype but can be classified into five genotypes (genotypes I–V, GI–GV) based on nucleic acid sequences. Historically, genotype III (GIII) was the predominant strain. However, since the 21st century, genotype I (GI) rapidly replaced GIII as the major genotype in China, Southeast Asia, and other regions. The live attenuated vaccine (LAV) SA14-14-2, licensed in China in 1988, was successfully exported to 13 countries, with cumulative vaccinations exceeding one billion doses. The vaccine seed virus SA14-14-2 belonged to genotype III. Whether this GIII-based vaccine provided sufficient protection against the currently circulating GI strains warranted systematic investigation. In this study, recent JEV isolates collected from China were subjected to genotypic analysis, followed by comprehensive evaluations including protective efficacy against challenge and serum neutralizing antibody levels. The results indicated that, despite antigenic differences between GIII and GI strains, no significant differences in protective efficacy post-challenge were observed. The SA14-14-2 LAV remained effective in preventing GI strain infection.

Nipah virus (NiV) is a highly pathogenic zoonotic pathogen. Since its discovery in 1998, recurrent epidemics have occurred in South and Southeast Asia, with a case fatality rate ranging from 40% to 100%. The outbreak in West Bengal, India in early 2026 has once again highlighted its severe threat to public health. To date, no licensed human vaccines or specific therapeutics against NiV are available worldwide. This review systematically summarizes the breakthroughs in antigen design for NiV vaccines, with a focus on conformational stabilization of prefusion F (pre-F) protein, chimeric G/F antigens, and multivalent nanoparticle strategies. In addition, we comparatively analyze the clinical progress of mainstream vaccine platforms, including viral vectors, mRNA and subunit vaccines. Given the sporadic nature and high mortality of NiV infection, the conventional licensing pathway relying on large-scale phase III clinical trials faces substantial practical obstacles. Accordingly, this article discusses adaptive adjustments in regulatory science. We propose several strategies to accelerate the clinical translation and emergency stockpiling of NiV vaccine candidates, including establishing unified correlates of protection thresholds, coordinating multinational regulatory resources, and optimizing the implementation of Animal Rule.