Dengue Vaccine (Dengvaxia, CYD-TDV):

• Dosing:
  • 3 doses, 6 months apart (0, 6, 12 months).
  • Rationale: The 3-dose schedule is based on clinical trials showing sustained efficacy.
• Duration of Protection:
  • Up to 6 years post-vaccination (based on long-term follow-up data).
  • Rationale: Efficacy wanes over time, with the highest protection in the first few years.
• Prevention Rate (Efficacy):
  • ~60% against symptomatic dengue (varies by serotype).
  • ~80% against severe dengue and hospitalization.
  • Rationale: Efficacy is higher in individuals with prior dengue infection (seropositive) compared to seronegative individuals.

• Key Considerations:
  • WHO Recommendation: Vaccination only for seropositive individuals (prior dengue infection) due to increased risk of severe disease in seronegative recipients.
  • Safety: Avoid in seronegative individuals to prevent vaccine-enhanced disease.