Dengue Literature Review

Vietnam

3 min read

Vietnam

Overview

Vietnam is a hyperendemic dengue country in Southeast Asia with year-round transmission dominated by Aedes aegypti in urban and peri-urban areas. Ho Chi Minh City (HCMC, formerly Saigon) in southern Vietnam is one of the most intensively studied dengue sites in the region, contributing foundational data on paediatric DHF/DSS — particularly in infants and young children. Vietnam’s unique epidemiological features include: (1) a very high incidence of dengue in infants, providing a natural cohort for studying primary infection DHF/DSS independent of ADE; (2) co-circulation of all four DENV serotypes; and (3) long-standing institutional collaboration between Children’s Hospital No.1 (HCMC), the Pasteur Institute (HCMC), and National Cheng Kung University (NCKU, Tainan, Taiwan) that has produced mechanistically detailed immunology research.

Key Points from Literature

Paediatric DHF/DSS — infants vs. children cohort (Hung2008)

Hung2008 - Anti-Platelet Anti-Endothelial Autoantibodies Vietnam enrolled 50 infants (<12 months) and 37 children (4–15 years) with confirmed DHF/DSS at Children’s Hospital No.1, HCMC (1998–2002):

  • Infants (predominantly primary infection): 49/50 had primary dengue (confirmed by IgM/IgG ELISA ratio). DEN-3 (n=10) and DEN-4 (n=4) identified by NS1 serotype-specific IgG ELISA. Age range 1–11 months (mean 7±2.5 months). Non-shock DHF n=36, DSS n=14.
  • Children (predominantly secondary infection): 33/37 (89.2%) had secondary dengue; 4/37 primary. Age range 4–15 years (mean 9.6±3.0 years). DEN-2 (n=3) and DEN-4 (n=14) by virus isolation and/or RT-PCR (Pasteur Institute HCMC + CDC Taipei). Non-shock DHF n=27, DSS n=10.

Key findings from this cohort:

  • Anti-platelet IgM autoantibodies elevated in both infants (16.5% vs 1.5% controls, p<0.001) and children (11.0% vs 3.2% controls, p<0.001)
  • Anti-endothelial cell antibodies: infants produced IgM only (17.6% vs 4.0%, p=0.003); children produced both IgM (46.0% vs 4.7%, p<0.001) and IgG (25.1% vs 2.6%, p<0.001)
  • Thrombomodulin (in vivo endothelial damage marker) significantly elevated in both infants (6.1 vs 2.7 pg/mL, p<0.001) and children (8.8 vs 2.4 pg/mL, p=0.01)
  • Autoantibody levels were not correlated with DHF severity, platelet counts, or haematocrit — consistent with a multi-mechanism model of DHF

NS1 molecular mimicry epitope mapping in Vietnamese DHF patients (Cheng2015)

Cheng2015 - NS1 P311-330 Anti-PDI Autoantibodies in DHF enrolled Vietnamese paediatric DHF (n=15) and DF (n=2) patients from HCMC, with autoantibody assays conducted at NCKU Tainan:

  • Anti-PDI, anti-HSP60, anti-vimentin, and anti-P311–330 IgM/IgG were significantly elevated in DHF vs. normal controls
  • The PDI-specific NS1 epitope was resolved to P311–330 (aa 311–330) within the C-terminal NS1 region (aa 311–352)
  • Anti-EC autoantibodies were infection-order independent (primary and secondary DHF comparable; caveat: n=2 primary DHF)
  • NS1 C-terminal deletion vaccine design implications: P311–330 must be excluded from NS1-based vaccine constructs to avoid anti-PDI cross-reactivity

Together, these two studies position HCMC as the primary site for the NS1 autoantibody mimicry mechanistic research in this wiki’s Southeast Asian cohorts.

Contradictions & Debates

  • The Hung2008 and Cheng2015 cohorts overlap geographically (both HCMC) but not temporally (Hung2008: 1998–2002; Cheng2015: dates not fully specified but post-2010 based on citation structure) and use different assay endpoints (flow cytometry vs. ELISA). The broad patterns are convergent but the methodological differences preclude direct numeric comparison.

Sources

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