Infectious disease
Does an earlier dengue infection protect children from Zika?
Open access · cc by · source: Europe PMC
Children who had caught dengue before were no less likely to be infected by Zika, but when infected they were about a third less likely to get sick with symptoms.
Study at a glance
- Design
- Cohort — Prospective community-based pediatric cohort (running since 2004) followed through the 2016-2017 Zika epidemic, with symptomatic cases tested at a health center and inapparent infections detected by paired annual blood samples.
- N
- N=3027 · 3,893 children took part during the study period; 3,027 with known dengue histories were in the symptomatic Zika analysis; 2,659 of these with paired annual sera were in the infection analysis.
- Population
- Children aged 2-14 years in a low-to-middle income district of Managua, Nicaragua
- Outcome
- Incidence of symptomatic Zika, incidence of total Zika virus infection, and the proportion of infections that were symptomatic, by prior dengue infection status
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Zika was very common: 560 children had symptomatic Zika, and total infection incidence was roughly 36.5 per 100 person-years. Prior dengue did not change the chance of being infected with Zika (IRR 0.98), but among infected children it lowered the rate of having symptoms (IRR 0.62), and it lowered the overall rate of symptomatic Zika (IRR 0.63). Girls and older children had higher rates of infection, and the early reproduction number was estimated at about 3.3-3.4.
Methodology
The researchers used a long-running dengue cohort of 3,893 children in Managua, Nicaragua, whose past dengue infections had been recorded for years. When Zika arrived in 2016, sick children were tested at the study health center, and yearly blood samples before and after the epidemic revealed silent (inapparent) infections. They compared Zika infection and symptom rates between children with and without earlier dengue, adjusting for age and sex.
Limitations
The study included only children, so it cannot say whether dengue immunity protects adults, and it did not examine serious outcomes such as birth defects or Guillain-Barre syndrome. Some children were excluded because their dengue histories or paired blood samples were incomplete, and infections were partly classified by a serological algorithm that could misclassify some cases. Symptomatic infections were only caught if families came to the health center, and shared mosquito exposure is an unmeasured confounder. As an observational study, it shows an association, not proof that dengue antibodies or T cells cause the protection.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
Susceptibility to infection and to disease are different quantities.
Pre-existing immunity can change the clinical picture without changing transmission: in 3,027 Nicaraguan children, prior dengue did not alter the risk of Zika infection (IRR 0.98) but lowered the chance of symptoms (IRR 0.62), and the early reproduction number was about 3.3-3.4.
Evidence for the claim as stated.
The European surveys model contact-driven, close-contact respiratory spread; Zika is mosquito-borne, so its reproduction number reflects vector ecology rather than human mixing. The Zika cohort shows how immunity modifies outcomes, not how contact matrices apply to it.
Same question, contrary or null result.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
The European surveys model contact-driven, close-contact respiratory spread; Zika is mosquito-borne, so its reproduction number reflects vector ecology rather than human mixing. The Zika cohort shows how immunity modifies outcomes, not how contact matrices apply to it.
Related papers in this topic
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