London: The current Zika epidemic in Latin America is likely to burn itself out within three years, researchers have predicted. Zika is a disease caused and spread through Aedes aegypti mosquito bites, and was declared a public health emergency of international concern by the World Health Organisation earlier this year.
The findings showed that the epidemic cannot be contained with existing control measures, but the next large-scale epidemic was unlikely to emerge for at least another ten years — although there is a possibility of smaller outbreaks in this period.
“Our analysis suggests that Zika spread is not containable, but that the epidemic will burn itself out within 2-3 years,” said lead author Neil Ferguson, Professor at Imperial College London.
The end of the epidemic attributes to the fact that people are unlikely to be infected with Zika twice, the researchers said.
“The current explosive epidemic will burn itself out due to a phenomenon called herd immunity. Because the virus is unable to infect the same person twice — thanks to the immune system generating antibodies to kill it — the epidemic reaches a stage where there are too few people left to infect for transmission to be sustained,” Ferguson explained.
However, any efforts to slow spread of the virus may in fact prolong the current epidemic, the researchers warned.
“Slowing transmission between people means the population will take longer to reach the level of herd immunity needed for transmission to stop. It might also mean that the window between epidemics — which we predict may be over a decade — could actually get shorter,” Ferguson added.
While the potential end of the epidemic is no doubt positive, it does raise issues for vaccine development, said the paper published in the journal Science. For the study, the team collated all existing data for Zika transmission across Latin America.
The team then used this information, alongside data on similar viruses such as dengue, to build a mathematical model to represent the current epidemic, and future waves of transmission.