# Long-term safety and effectiveness of Dengvaxia in the Philippines

> **NIH NIH R01** · UNIVERSITY OF HAWAII AT MANOA · 2024 · $615,068

## Abstract

Abstract
The four serotypes of dengue virus (DENV1–4) are the leading cause of mosquito-borne viral diseases in
humans. Dengvaxia, the first licensed dengue vaccine, was recommended for individuals aged 9–45 years in
2016. In the Philippines, a school-based vaccination program was launched in April 2016 with >830,000
children receiving Dengvaxia without prior serological testing. Subsequently, DENV-seronegative children who
received Dengvaxia developed severe disease after breakthrough DENV infection (BTDI). This resulted in the
revised recommendation in 2018 that Dengvaxia be administered only to DENV-seropositive individuals. Thus,
thousands of Filipino children are at higher risk of severe dengue disease. Studies have shown the efficacy of
Dengvaxia waned over time especially among baseline DENV-seronegative recipients, underscoring a critical
need for elucidation of antibody and T-cell responses induced by Dengvaxia. Our understanding of Dengvaxia
was primarily based on efficacy trials with 3-dose regimen. A knowledge gap exists regarding the risk of severe
disease and effectiveness in the real world, where most individuals received only 1 or 2 doses and presented
with BTDI. In collaboration with the Research Institute for Tropical Medicine, our recent study demonstrated the
feasibility of our DENV1–4 nonstructural protein 1 (NS1) IgG ELISA to determine the baseline DENV
serostatus of Dengvaxia recipients during both BTDI and other febrile illness (OFI) in the Philippines.
Our long-term goal is to facilitate the development of next-generation dengue vaccines and to reduce the global
disease burden of dengue. The objective is to understand the long-term effects of Dengvaxia, a chimeric yellow
fever tetravalent dengue vaccine, and the immune responses induced in the Filipino population. The central
hypothesis is that Dengvaxia induces antibody and T-cell responses inferior to natural infection, leading to
limited type-specific neutralizing antibodies, weak T-cell responses and waning vaccine efficacy especially for
baseline DENV-naïve recipients. The first aim is to determine the baseline DENV serostatus of Dengvaxia
recipients in the Philippines and assess the long-term safety and effectiveness of Dengvaxia. The second aim is
to characterize antibody and T-cell responses induced by Dengvaxia prior to and after BTDI.
The proposed research is innovative as it combines RT-PCR and IgM ELISA used in routine dengue fever
surveillance and our recently validated DENV1−4 NS1 IgG ELISA to determine baseline DENV serostatus
under field conditions and provides new insights into the safety and effectiveness of Dengvaxia after mass
vaccination through a manufacturer-independent study as opposed to that derived from vaccine efficacy trials.
Given that previous immunogenicity studies of Dengvaxia primarily focused on neutralizing antibody titers, our
in-depth study of antibody responses both qualitatively and quantitatively and T-cell responses to structural
...

## Key facts

- **NIH application ID:** 10946702
- **Project number:** 1R01AI186073-01
- **Recipient organization:** UNIVERSITY OF HAWAII AT MANOA
- **Principal Investigator:** Wei-Kung Wang
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $615,068
- **Award type:** 1
- **Project period:** 2024-08-01 → 2029-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10946702

## Citation

> US National Institutes of Health, RePORTER application 10946702, Long-term safety and effectiveness of Dengvaxia in the Philippines (1R01AI186073-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10946702. Licensed CC0.

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