Tetravalent Dengue Vaccine Trial

Advancing Dengue Vaccine Research

Tackling the Global Burden of Dengue

Dengue is one of the most rapidly spreading mosquito-borne viral diseases worldwide, placing nearly half of the global population at risk. The disease is caused by four closely related dengue virus serotypes and is transmitted primarily by Aedes mosquitoes. Each year, hundreds of millions of infections occur globally, with severe cases leading to hospitalization and potentially life-threatening complications such as dengue haemorrhagic fever and dengue shock syndrome.

Countries across Asia, Latin America, and other tropical regions carry a particularly heavy burden, highlighting the urgent need for effective vaccines capable of providing broad protection against all dengue virus serotypes.

Case Study: Phase 3 Tetravalent Dengue Vaccine Trial

Study Overview

The Phase 3 Tetravalent Immunization against Dengue Efficacy Study (TIDES) evaluated the safety and efficacy of a tetravalent dengue vaccine candidate developed to protect against all four dengue virus serotypes.

This randomized, double-blind, placebo-controlled clinical trial enrolled more than 20,000 children and adolescents aged 4–16 years across multiple dengue-endemic countries, including Sri Lanka, Thailand, Brazil, Colombia, Panama, the Philippines, and others.

Participants were randomly assigned in a 2:1 ratio to receive either the dengue vaccine candidate or placebo. The study regimen consisted of two doses administered three months apart, followed by long-term monitoring to assess vaccine protection and safety.

Sri Lanka’s Contribution to the Trial

Sri Lanka played an important role in the multinational trial (SLCTR/2016/019).

Clinical research teams in Sri Lanka contributed to:

Participant recruitment in dengue-endemic populations
Clinical monitoring and surveillance for febrile illness
Laboratory confirmation of dengue infection
Safety monitoring and adverse event reporting
Long-term participant follow-up

The involvement of Sri Lankan research sites provided valuable epidemiological insights from a region with significant dengue transmission, strengthening the global evidence base for the vaccine’s effectiveness. Across participating Sri Lankan sites, retention reached approximately 98.7% over a seven-year follow-up period, highlighting the strength of site coordination, community engagement, and participant management strategies.

Study Methodology

The study incorporated robust clinical trial procedures designed to ensure accurate detection and evaluation of dengue cases.

Key methodological components included:

Active surveillance for febrile illness among participants
Laboratory confirmation of dengue infection using RT-PCR
Assessment of baseline dengue serostatus
Monitoring of vaccine safety and serious adverse events
Long-term follow-up to evaluate sustained protection

This approach enabled researchers to assess vaccine performance across different populations, including both dengue-naïve individuals and those previously exposed to the virus.

Key Results

The trial demonstrated promising outcomes for the tetravalent dengue vaccine candidate:

Approximately 61% efficacy against symptomatic dengue infection
Around 84% reduction in dengue-related hospitalizations
Protection observed against multiple dengue virus serotypes
A favourable safety profile across diverse populations

Long-term follow-up studies further showed sustained protection several years after vaccination, reinforcing the vaccine’s potential role in reducing the global dengue burden.