Vaccinating against dengue fever could increase outbreaks of Zika, suggests new research out of York University and Xi’an Jiaotong University in China.
The research identifies a potentially serious public health concern. More than a third of the world’s population lives in areas where dengue is endemic and cases of co-infection with Zika have already been reported.
Conducted at York University’s Laboratory for Industrial and Applied Mathematics using mathematical modelling, the research was led by Biao Tang, an exchange PhD student from Xi’an Jiaotong University, in collaboration with York Professor Jianhong Wu and Tang’s supervisor, Professor Yanni Xiao at Xi’an Jiaotong University. As dengue and Zika are both part of the Flaviviridae family transmitted through a common mosquito host, the researchers wanted to know how vaccinating for one would affect the incidence of the other.
“Vaccinating against one virus could not only affect the control of another virus, it could, in fact, make it easier for the other to spread,” says Wu. “Recent evidence suggests that dengue virus antibodies can enhance the Zika virus infection. For that reason, we developed a new math model to investigate the effect of dengue vaccination on Zika outbreaks.”
The paper, “Implication of vaccination against dengue for Zika outbreak,” was published in Scientific Reports.
The team’s model shows that vaccinations for dengue increase the number of people contracting Zika. It also shows that the more people in a particular population that are vaccinated against dengue, the earlier and larger the Zika outbreak. The research also found that the most effective way to minimize the unintended effect of dengue vaccinations on Zika outbreaks is an integrated strategy that includes mosquito control.
“We concluded that vaccination against dengue among humans can significantly boost Zika transmission among the population and hence call for further study on integrated control measures on controlling dengue and Zika outbreak,” says Xiao.