387: Homotypic Dengue Reinfections and Long-Term Antibody Decay

Andrade J et al., PNAS - Analysis of three long-term cohorts in the Philippines and Thailand shows antibody titers wane over years and that homotypic dengue reinfections are common and required to explain population-level age–titer patterns. Key terms: dengue, homotypic reinfection, antibody kinetics, cohort study, mathematical modelling.

Study Highlights:
The authors analyzed serology and PCR surveillance from three cohorts (N = 4,268) in Cebu, Philippines and Kamphaeng Phet, Thailand with up to 11 years of follow-up. Individual titers after infection show biexponential decay: a rapid short-term fall (~2 months half-life) followed by a slow long-term decline (half-life ~4–8 years) that slows with age. Catalytic models that allow waning homotypic immunity and reinfection are required to reproduce observed age-specific infection rates and mean titers, estimating many individuals experience multiple homotypic reinfections across life in high-endemic settings.

Conclusion:
Waning long-term antibody titers and consequent homotypic reinfections are a key feature of endemic dengue transmission; vaccines that mimic natural infection may not provide lifelong protection and control strategies should account for repeated immune-stimulating events across ages.

Music:
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Article title:
Long-term antibody dynamics challenge the paradigm of lifelong homotypic immunity to dengue virus

First author:
Andrade J

Journal:
PNAS

DOI:
10.1073/pnas.2606206123

Reference:
Andrade J, Mitard de Girardie A, Huang AT, et al. Long-term antibody dynamics challenge the paradigm of lifelong homotypic immunity to dengue virus. PNAS. 2026;123(22):e2606206123. doi:10.1073/pnas.2606206123

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

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QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-06-09.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript's coverage of dengue immunity dynamics, cohort data, subclinical infection prevalence, modeling of homotypic reinfection, age-related patterns, and public health/vaccine implications. Also checked limitations and caveats discussed in the article are echoed in the transcript.
- transcript topics: DENV serotypes and lifelong immunity paradigm; Cohort data and serology methods (PRNT, HI); Subclinical infections and catalytic modeling; Two-phase antibody decay (short-term and long-term); Homotypic reinfection and population immunity; Age-specific infection risk and force of infection

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Three cohorts totaling N = 4,268 participants across Cebu, Philippines and Kamphaeng Phet, Thailand
- Approximately 94% of infections are subclinical
- Antibody titers show biexponential decay after infection: a rapid short-term drop followed by a slower long-term decline
- Short-term half-life around 2 months; long-term half-life on the order of years (varying by cohort; Philippines ~6.7 years; Thailand ~4.0 years)
- By age ~40 in highly endemic settings, ~60% of individuals have experienced a homotypic reinfection
- Mean population titers peak in early adulthood (Philippines ~22 years; Thailand ~48 years) and slowly decline thereafter

QC result: Pass.