Humoral and cellular immunogenicity and safety following a booster dose of a tetravalent dengue vaccine 5+ years after completion of the primary series in Singapore: 2-year follow-up of a randomized phase II, placebo-controlled trial.

The tetravalent dengue vaccine (CYD-TDV) is approved for use as a 3-dose series for the prevention of dengue in seropositive individuals ≥9 years. A randomized, placebo-controlled, phase II study of a booster dose of CYD-TDV in individuals who completed the 3-dose schedule >5 years previously (NCT02824198), demonstrated that a booster restored neutralizing antibody titers to post-dose 3 levels. We present additional immunogenicity assessments up to 24 months post-booster, and B- and T-cell responses in a participant subset.

Immune Response Persistence and Safety of a Booster Dose of the Tetravalent Dengue Vaccine in Adolescents and Adults Who Previously Completed the 3-dose Schedule 4-5 Years Earlier in Latin America: A Randomized Placebo-controlled Trial.

Background: We previously described an increased immune response 28 days after a booster dose of the live, attenuated, tetravalent dengue vaccine (CYD-TDV) in healthy adolescents and adults in Latin America (CYD64, NCT02623725). This follow-up study evaluated immune response persistence and safety of a CYD-TDV booster dose up to Month (M) 24 post-booster.

Methods: This study included 250 participants who previously received 3 primary doses of CYD-TDV in the CYD13 (NCT00993447) and CYD30 (NCT01187433) studies, and who were randomized 4-5 years later to receive a CYD-TDV booster or placebo (3:1).

Cytokine Profile of Children Hospitalized with Virologically-Confirmed Dengue during Two Phase III Vaccine Efficacy Trials.

Background: Two large-scale efficacy studies with the recombinant yellow fever-17D-dengue virus, live-attenuated, tetravalent dengue vaccine (CYD-TDV) candidate undertaken in Asia (NCT01373281) and Latin America (NCT01374516) demonstrated significant protection against dengue disease during two years' active surveillance (active phase). Long-term follow up of participants for breakthrough disease leading to hospitalization is currently ongoing (hospital phase).

Methodology/principal Findings: We assessed the cytokine profile in acute sera from selected participants hospitalized (including during the active phase) up to the beginning of the second year of long-term follow up for both studies.