Current worldwide circulation and burden of dengue and zika
Arboviruses, particularly Dengue virus (DENV) and Zika virus (ZIKV), represent a massive and escalating global health threat. Transmitted primarily by infected Aedes mosquitoes, Dengue is now endemic in over 100 countries. It puts roughly half of the global population at risk, causing an estimated 400 million infections, 100 million symptomatic cases, and up to 40,000 deaths annually1. Zika virus, which triggered a global public health emergency during the 2015–2016 epidemic, continues to circulate widely (Figure 1)1.
While often asymptomatic, ZIKV poses a devastating risk during pregnancy, leading to Congenital Zika Syndrome (CZS)—which includes severe microcephaly—as well as neurological complications like Guillain-Barré syndrome in adults2. The geographic footprints of both viruses are rapidly expanding due to urbanization, global travel, and climate change, underscoring the critical and immediate need for safe, globally deployable vaccines.
Clinical research status of arbovirus vaccines and the ADE challenge
The clinical development of vaccines against DENV and ZIKV has historically been complicated by a severe immunological hurdle: antibody-dependent enhancement (ADE). Because dengue exists as four distinct, co-circulating serotypes (DENV1–4), and because DENV and ZIKV share significant structural homology, previous infections or poorly designed vaccines can induce cross-reactive, sub-neutralising antibodies. These antibodies often target the highly conserved, immunodominant “fusion loop” of the viral Envelope (E) monomer. Instead of neutralising the virus, these antibodies facilitate viral entry into host immune cells, paradoxically worsening disease severity upon subsequent infection. Consequently, modern clinical research has shifted away from simply inducing broad antibody responses toward highly targeted, structure-guided approaches.
To avoid ADE, next-generation subunit and mRNA vaccines are heavily focused on utilising stabilised Envelope (E) protein dimers3. By locking the E protein in its native, dimeric conformation, researchers can effectively hide the dangerous, ADE-prone fusion loop while safely exposing highly potent, dimer-dependent epitopes that drive robust and safe neutralising immunity.
While early-generation live-attenuated platforms currently dominate the late-stage pipeline, the ongoing threat of ADE has spurred a diverse array of advanced vaccine candidates with recombinant E dimers in active clinical trials:
Research applications
Arbovirus envelope (E) protein dimers have proven to be highly efficient tools in vaccine research. They serve as vaccine antigens, design scaffolds for safer vaccines, display antigens in particle systems, and assay reagents for antibody analysis. Recent studies demonstrate that stable E dimers improve antigen quality, direct immune responses toward potent neutralising epitopes, and reduce the targeting of ADE-prone sites, making them highly valuable for immune-response profiling in human samples.
Metz et al. investigated whether a stable Zika virus (ZIKV) E protein dimer outperforms an E monomer as a subunit vaccine antigen. In mouse immunisation studies, the E dimer served as both the immunogen and the binding target. They found that only the native-like E dimer was well recognised by strongly neutralizing antibodies and successfully induced protective responses in mice, establishing it as a superior subunit antigen4 (Figure 2).
Similarly, Slon-Campos et al. utilised a covalently stabilised ZIKV E dimer to engineer a safer subunit vaccine. Their goal was to preserve protective dimer-dependent epitopes while hiding the fusion loop, which is linked to dengue (DENV) cross-reactivity and ADE. Serving as both the immunogen and design scaffold, the engineered E dimer induced specific antibodies that protected against ZIKV during pregnancy without triggering dangerous DENV cross-reactivity, highlighting its dual benefits for protection and safety5 (Figure 3).
In another application, Phan et al. developed a tetravalent dengue subunit vaccine by displaying stabilised DENV1–4 soluble E dimers on CPQ liposomes. Functioning as multivalent immunogens, these stabilised dimers elicited stronger neutralising responses than wild-type soluble E proteins, and liposome display further enhanced immunogenicity. Crucially, the tetravalent mixture produced type-specific neutralising antibodies without significant immune interference, demonstrating that E dimers effectively support advanced multivalent vaccine design6. Beyond acting as immunogens, Lay et al. showcased the utility of E dimers as precise analytical tools. They used recombinant DENV2 EDIII, soluble E, and sE-dimer proteins to create a multiplex assay and antibody isolation workflow to quantify specific antibody groups in human plasma. Acting as a reference and isolation reagent, the E dimer successfully separated and enriched distinct antibody subsets. This confirms that E dimers are not only effective vaccine antigens but also indispensable tools for immune profiling and distinguishing between protective and potentially harmful antibody responses7.
To support this critical shift toward structure-guided antigen design, Sino Biological offers a comprehensive portfolio of high-quality recombinant Arbovirus envelope (E) proteins, including highly stable E dimers. Engineered to meet the rigorous demands of advanced vaccine research, these E dimers accurately preserve the native-like dimeric conformation, as validated by SEC-MALS. Whether one is designing safer subunit vaccines, developing multivalent nanoparticle displays, or building multiplex immune-profiling assays to isolate specific antibody subsets, Sino Biological’s recombinant DENV and ZIKV E dimers provide the reliable, highly pure antigens required for success.
References
1. Lim, A. et al. The overlapping global distribution of dengue, chikungunya, Zika and yellow fever. Nat. Commun. 16, 3418 (2025).
2. Rabe, I. B. et al. A Review of the Recent Epidemiology of Zika Virus Infection. Am. J. Trop. Med. Hyg. https://doi.org/10.4269/ajtmh.24-0420 (2025) doi:10.4269/ajtmh.24-0420.
3. Unali, G. & Douam, F. Orthoflavivirus Vaccine Platforms: Current Strategies and Challenges. Vaccines (Basel). 13, 1015 (2025).
4. Metz, S. W. et al. Oligomeric state of the ZIKV E protein defines protective immune responses. Nat. Commun. 10, 4606 (2019).
5. Slon-Campos, J. L. et al. A protective Zika virus E-dimer-based subunit vaccine engineered to abrogate antibody-dependent enhancement of dengue infection. Nat. Immunol. 20, 1291–1298 (2019).
6. Phan, T. T. N. et al. Multivalent administration of dengue E dimers on liposomes elicits type-specific neutralizing responses without immune interference. NPJ Vaccines 10, 119 (2025).7. Lay, S. et al. Toward a deeper understanding of dengue: novel method for quantification and isolation of envelope protein epitope-specific antibodies. mSphere 10, (2025).
