Shifting patterns of dengue three years after Zika virus emergence in Brazil

Abstract

AbstractThe Zika virus (ZIKV) emerged in Brazil in 2015, causing large outbreaks across South America and the Caribbean. In the years that followed, many countries in these areas reported exceptionally low circulation of Dengue virus (DENV), which later resurged in 2018-2019. Several hypotheses have been proposed to explain low DENV transmission, yet no consensus has been reached so far. We show that while short-term cross-protection induced by ZIKV can explain the temporary disappearance of DENV, it also predicts, in contrast with observations, a rising mean age of DENV incidence in the post-ZIKV era. We further demonstrate that disease enhancement of DENV, especially in primary infections in ZIKV-positive hosts, is required to remedy these shortfalls. Our results suggest that both population-level immunity to DENV and ZIKV contributed positively to the reduction in mean age of DENV incidence.