Waning Japanese Encephalitis Virus Immunity Linked to Increased Dengue Disease Severity in Humans

Waning Japanese Encephalitis Virus Immunity Linked to Increased Dengue Disease Severity in Humans

Japanese Encephalitis Virus (JEV) and Dengue Virus (DENV) are two of the most significant mosquito-borne viral diseases affecting humans in Asia. While both viruses are transmitted by the same vector, Culex tritaeniorhynchus for JEV and Aedes spp. for DENV, they belong to different viral families and have distinct pathogenesis profiles. Recent studies have suggested that pre-existing immunity to JEV may influence the severity of DENV infection in humans. In this blog post, we will discuss the findings of a recent study that investigated the relationship between waning JEV immunity and DENV disease severity.

The Study

A recent study published in Science Translational Medicine investigated the relationship between JEV immunity and DENV disease severity in humans. The study found that individuals with waning JEV immunity had increased DENV disease severity. The researchers used a combination of epidemiological, immunological, and molecular approaches to analyze the relationship between JEV and DENV infections.

Immune Response and Cross-Reactivity

The immune response to JEV and DENV infections involves the activation of various immune cells, including mast cells (MCs) (16). Beyond antigen specificity, the concentrations of neutralizing antibodies and the quality of cell responses, was shown to be protective (35). In a study on JEV and DENV co-infection, it was observed that JEV-specific antibodies can cross-react with DENV, leading to antibody-dependent enhancement (ADE) of DENV infection (23).

Epidemiological Evidence

Epidemiological studies have shown that areas with high JEV vaccination coverage have lower DENV disease severity (12). Conversely, areas with low JEV vaccination coverage have higher DENV disease severity (34). These findings suggest that JEV immunity may have a protective effect on DENV disease severity.

Mechanisms Underlying the Relationship

The mechanisms underlying the relationship between JEV immunity and DENV disease severity are complex and multifactorial. One possible explanation is that JEV-specific antibodies can cross-react with DENV, leading to ADE of DENV infection (23). Another possibility is that JEV immunity can modulate the immune response to DENV infection, leading to a more severe disease outcome (35).

Conclusion and Implications

In conclusion, the study provides evidence that waning JEV immunity is linked to increased DENV disease severity in humans. These findings have significant implications for public health policy and vaccine development. For example, JEV vaccination programs may need to be re-evaluated in the context of DENV disease severity. Additionally, the development of vaccines that can provide dual protection against JEV and DENV may be a promising strategy for reducing the burden of these diseases in Asia.

• Further studies are needed to understand the mechanisms underlying the relationship between JEV immunity and DENV disease severity.
• JEV vaccination programs may need to be re-evaluated in the context of DENV disease severity.
• The development of vaccines that can provide dual protection against JEV and DENV may be a promising strategy for reducing the burden of these diseases in Asia.

Read the full study: https://www.science.org/doi/10.1126/scitranslmed.ads9572