Recent progress on sanofi pasteur's dengue vaccine candidate.

Area of Science:

• Vaccinology
• Virology
• Immunology

Background:

• Dengue fever poses a significant global health threat, necessitating effective preventative measures.
• The Sanofi Pasteur tetravalent dengue vaccine (TV) is a novel recombinant live attenuated vaccine.
• It utilizes a yellow fever vaccine (YF 17D) backbone with genes from all four dengue serotypes.

Purpose of the Study:

• To evaluate the reactogenicity, viraemia induction, and antibody responses of the dengue tetravalent vaccine (TV).
• To assess the vaccine's safety and immunogenicity in Phase II clinical trials across different populations.

Main Methods:

• Three Phase II randomized trials were conducted in the USA, the Philippines, and Mexico.
• Participants received a three-dose regimen of dengue TV over 12 months or a control vaccine/placebo followed by two TV doses.
• Adverse events, viraemia, and antibody responses (seroconversion) were monitored.

Main Results:

• The majority of adverse events were mild to moderate and transient.
• No evidence of viraemia induction was reported after initial dengue TV administration.
• 100% seroconversion for all four serotypes was observed in flavivirus-naive US adults; 88-100% in naive Mexican children.
• Seropositivity increased with each dose in the Philippines, where baseline immunity was high.

Conclusions:

• The dengue tetravalent vaccine (TV) demonstrates a favorable safety profile and robust immunogenicity.
• High seroconversion rates across all four serotypes suggest potential efficacy.
• Further clinical development, including an efficacy trial in Thailand, is ongoing.