Dengue serotype-specific immunity after natural infection is lifelong, but cross-serotype (heterologous) immunity is temporary. This has which important epidemiological consequence?
- A Primary dengue infection is always the most severe
- B A person infected with one serotype cannot be infected by another
- C Secondary infection with a different serotype carries higher risk of severe dengue due to antibody-dependent enhancement ✓
- D Herd immunity is achievable with vaccination against a single serotype
Correct answer: C. Secondary infection with a different serotype carries higher risk of severe dengue due to antibody-dependent enhancement
Explanation
Antibody-Dependent Enhancement (ADE) explains severe dengue (dengue haemorrhagic fever/dengue shock syndrome) predominantly occurring in secondary heterologous serotype infections. Pre-existing cross-reactive antibodies from primary infection facilitate uptake of the second serotype into FcγR-bearing monocytes/macrophages, amplifying viral replication and triggering a cytokine storm. This is why countries with multiple co-circulating serotypes have higher DSS burden.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.