NEWS – A recent study published in Science Translational Medicine has provided crucial insights into the immune mechanisms that protect against dengue fever

HIGHLIGHTS

Background & Challenge

• Dengue, caused by four serotypes (DENV1–4), is the most common vector-borne viral disease, threatening half the world’s population.
• First infection often increases the risk of severe disease upon reinfection with a different serotype — a phenomenon known as antibody-dependent enhancement (ADE).
• Existing vaccines (Dengvaxia, QDENGA) work best for those with prior exposure; dengue-naïve individuals face ADE risk.

The Study

• Investigated immune markers in 2,996 children (aged 9–14) in Cebu, Philippines, during a major dengue outbreak (2017–2022).
• Cohort: 1,782 vaccinated, rest unvaccinated.
• Aim: Identify immune components linked to broad, cross-serotype protection.

Key Finding — EDE-like Antibodies

• Envelope Dimer Epitope (EDE)-like antibodies emerged as strong markers of “secondary immunity” (after ≥2 infections).
• Prevalence: 81.8%–90.1% in secondary immunity vs. only 4%–12% in primary immunity cases.
• Strong correlation with neutralisation of all four serotypes.

Protective Role

• Both vaccination and natural infection boosted EDE-like, binding, and neutralising antibodies.
• Higher EDE-like antibody levels linked to lower risk of:
  • Symptomatic dengue
  • Dengue with warning signs
  • Hospitalisation
• More protective against disease severity than infection itself.

Mechanistic Insight

• EDE-like antibodies explained:
  • 42%–65% of protection from mature virus-neutralising antibodies
  • 41%–75% from general E protein-binding antibodies
• Indicates EDE-like antibodies are the primary driver of broad protection.

Implications & Future

• Potential to use EDE-like antibodies as markers for vaccine efficacy trials.
• May guide design of universal dengue vaccines targeting robust EDE antibody responses.
• Limitations: Limited case numbers for all serotypes; restricted monoclonal antibody panel.