• Neutralizing antibodies (seropositivity rates and GMTs) to each dengue virus serotype, 30 days after the dengue vaccine booster dose
  

• Safety
  
• Occurrence of solicited adverse events (AE) within 21 days follow-up after the dengue vaccine dose; Occurrence of unsolicited non-serious AEs within 31 days (days 0-30) after the dengue vaccine dose;
  
• Occurrence of serious adverse events (SAEs) within 31 days (days 0-30) after the dengue vaccine dose;
  
• Occurrence of alert values for safety laboratory determinations within 31 days after the dengue vaccine dose;
  
• Occurrence of dengue (suspected or confirmed) that prompted evaluation by a physician after the conclusion of Dengue-003 to the one year follow-up visit, and during Dengue-005, (with clinical outcome);
  
• Occurrence of hospitalized dengue for five years following the two-dose primary vaccination series;
  
• Immunogenicity
  
• Flavivirus immunity before administration of the dengue vaccine dose, assessed as the ratio of DEN IgM:IgG by isotype capture EIA in serum collected at the time of vaccination and 30 days after the dengue vaccine booster dose;
  
• Tetravalent N antibody, 30 days after the dengue vaccine booster dose;
  
• Tetravalent N antibody, assessed the day of dengue vaccine booster dose administration;
  
• Neutralizing antibodies (seropositivity rates and GMT) to each dengue virus serotype, before the dengue vaccine booster dose at Visit 1;
  
• Presence of dengue viremia 10 days after the dengue vaccine dose;
  
• Tetravalent N antibody and neutralizing antibodies (seropositivity rates and GMT) to each dengue virus serotype one year after the booster dose.
  

Follow-up of Dengue-003 Study (in Dengue-003; 7 Thai children received two doses of dengue vaccine six months apart followed by two doses of JE vaccine. In this study the same children will receive a booster dose approximately one year after the primary vaccination series. A one year safety follow-up after the primary vaccination series and a 4 year safety follow-up after the booster dose (one visit each year for 4 years) will be conducted. Blood samples will be collected before the booster dose and one month and again one year after the booster.

Inclusion Criteria:

• Subjects who received two doses of dengue vaccine in the Dengue-003 study.
• Subjects whose parents sign an informed consent form for participation.

Exclusion Criteria:

• None