A 10-year-old seronegative child living in a dengue endemic region is offered the CYD-TDV (Dengvaxia) vaccine. The reason this vaccine is NOT recommended for dengue-seronegative individuals is:
- A It fails to produce neutralising antibodies without prior natural infection
- B It causes vaccine-derived dengue viraemia transmitted by Aedes mosquitoes
- C It increases the risk of severe dengue and hospitalisation on subsequent wild infection, mimicking a silent primary infection ✓
- D It produces false positive NS1 antigen results for life
Correct answer: C. It increases the risk of severe dengue and hospitalisation on subsequent wild infection, mimicking a silent primary infection
Explanation
CYD-TDV behaves like an asymptomatic primary dengue infection in a seronegative recipient. When such a person later encounters wild virus, the immune response reproduces the antibody dependent enhancement phenomenon, raising the risk of severe dengue and hospitalisation. This safety signal led WHO to restrict the vaccine to confirmed seropositive individuals aged 9 to 45 years in endemic settings. Immunogenicity in naive subjects is actually adequate, so option A is wrong.
Reference: Park's Textbook of Preventive and Social Medicine, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.