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PLoS Negl Trop Dis. 2016 Feb 5;10(2):e0004398. doi: 10.1371/journal.pntd.0004398. eCollection 2016 Feb.

Incomplete Protection against Dengue Virus Type 2 Re-infection in Peru.

Author information

1
U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Perú
2
Indiana University School of Public Health, Bloomington, Indiana, United States of America.
3
Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America.
4
Department of Entomology and Nematology, University of California, Davis, Davis, California, United States of America.
5
Department of Biology, Andrews University, Berrien Springs, Michigan, United States of America.
6
Universidad Nacional de la Amazonía Peruana, Iquitos, Perú
7
Dirección Regional de Salud Loreto, Iquitos, Perú
8
University of New Mexico, Albuquerque, Albuquerque, New Mexico, United States of America.

Abstract

BACKGROUND:

Nearly half of the world's population is at risk for dengue, yet no licensed vaccine or anti-viral drug is currently available. Dengue is caused by any of four dengue virus serotypes (DENV-1 through DENV-4), and infection by a DENV serotype is assumed to provide life-long protection against re-infection by that serotype. We investigated the validity of this fundamental assumption during a large dengue epidemic caused by DENV-2 in Iquitos, Peru, in 2010-2011, 15 years after the first outbreak of DENV-2 in the region.

METHODOLOGY/PRINCIPAL FINDINGS:

We estimated the age-dependent prevalence of serotype-specific DENV antibodies from longitudinal cohort studies conducted between 1993 and 2010. During the 2010-2011 epidemic, active dengue cases were identified through active community- and clinic-based febrile surveillance studies, and acute inapparent DENV infections were identified through contact tracing studies. Based on the age-specific prevalence of DENV-2 neutralizing antibodies, the age distribution of DENV-2 cases was markedly older than expected. Homologous protection was estimated at 35.1% (95% confidence interval: 0%-65.2%). At the individual level, pre-existing DENV-2 antibodies were associated with an incomplete reduction in the frequency of symptoms. Among dengue cases, 43% (26/66) exhibited elevated DENV-2 neutralizing antibody titers for years prior to infection, compared with 76% (13/17) of inapparent infections (age-adjusted odds ratio: 4.2; 95% confidence interval: 1.1-17.7).

CONCLUSIONS/SIGNIFICANCE:

Our data indicate that protection from homologous DENV re-infection may be incomplete in some circumstances, which provides context for the limited vaccine efficacy against DENV-2 in recent trials. Further studies are warranted to confirm this phenomenon and to evaluate the potential role of incomplete homologous protection in DENV transmission dynamics.

PMID:
26848841
PMCID:
PMC4746126
DOI:
10.1371/journal.pntd.0004398
[Indexed for MEDLINE]
Free PMC Article

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