Zika infection increases future risk for severe dengue
Prior Zika virus infection can significantly increase the risk for severe dengue, similar to a prior dengue infection, which may pose issues for vaccine development for both viruses, according to a study published in Science.
“While the dengue epidemic was going on, we were noticing that there were a lot more cases than we were expecting, and so we were analyzing this and started seeing this tendency for more cases,” Eva Harris, PhD, professor of infectious diseases and vaccinology and director of the Center for Global Public Health at the University of California, Berkeley School of Public Health, told Healio.
“From there, we were able to perform a finer analysis and extend that to look at disease severity. What we found was not only was there more symptomatic disease, but there was also an enhancement of severe disease,” Harris said.
Harris and colleagues estimated the probability of symptomatic dengue virus serotype 2 (DENV2) during the 2019 to 2020 epidemic based on Zika virus and dengue infection histories. They analyzed pediatric cohorts in Nicaragua that experienced sequential dengue virus 1 (DENV1), DENV2 and dengue virus 3 (DENV3) epidemics from 2004 to 2015, Zika epidemics from 2016 to 2017 and DENV2 epidemics from 2018 to 2020.
In the study, the researchers found that the risk for symptomatic DENV2 and severe disease was increased by the presence of one prior Zika infection, one prior dengue infection or one prior dengue infection, followed by one Zika infection. However, multiple prior dengue infections reduced dengue risk.
The researchers also noted that high pre-existing anti-dengue antibody titers had a protective effect against DENV1, DENV3 and Zika, and intermediate titers activated by previous dengue or Zika infection increased future risk of DENV2 disease and severity and DENV3 severity.
“The most important thing that we want to do in the future is to maintain this cohort so that we can look not only at the effect on DENV2 because we happen to have a DENV2 epidemic, but the other serotypes,” Harris said.