Our study revealed that IgG and IgM antibodies to JEV, WNV, and TBEV were frequently detected in dengue‐confirmed patients with identified DENV serotypes, suggesting that these anti‐JEV/WNV/TBEV serological positives likely reflect cross‐reactivity or limited specificity of the assays rather than true co‐infections or prior exposures to JEV, WNV, or TBEV. Here, CD40LG is linked to dengue disease.