Zika virus vaccine may take 'several years'

THE long-term prospects for a vaccine against Zika virus are promising, but don't expect it too soon.

That's according to Immunology Professor Andrew Taylor-Robinson who heads up an Infectious Diseases Research Group at CQUniversity Australia.

"The rapid rise in the number of reported clinical cases of Zika in South and Central America over the span of a few months in late 2015 and early 2016 suggests a real risk of a global epidemic of this mosquito-transmitted viral infection," Dr Taylor-Robinson explains.

He said globalisation of the human population and the complexity of additional modes of transmission of the virus exacerbate the threat.

"Currently, no anti-Zika vaccine is available and while this has now been prioritised by multiple funding agencies, it may take several years to come to commercial fruition.

"The fact that Zika is closely related to yellow fever and Japanese encephalitis viruses (both of which have effective vaccines), offers hope that the fast-tracked preparation of a candidate vaccine is feasible."

However, because the virus poses the most risk to pregnant women, clinical trials will pose huge challenges.

"Performing clinical trials on pregnant women would provide ethical and practical challenges to overcome before licensure is granted for administration to the general public."

Despite the fact that a candidate vaccine could be at the pre-clinical trial stage by the end of 2016, it could take years for the clinical trials to be approved and conducted.

"While attaining ethical approval for, and performing, tests of vaccine safety and efficacy in humans can be laboriously slow at the best of times, the due process for any prototype vaccine that is given to pregnant women is understandably subject to rigorous scrutiny.

"This is especially pertinent to Zika since the gravest manifestation of infection affects pregnancy."

While the world awaits a preventative vaccine, alternative public health strategies must be employed.

Dr Taylor-Robinson said vector control programs to target mosquito breeding are required in order to limit the global spread of this disease.

Zika virus

Zika virus is transmitted to humans by yellow fever mosquitoes (aedes aegypti).

It causes mild fever and rash. Other symptoms include muscle pain, joint pain, headache, pain behind the eyes and conjunctivitis.

Zika virus disease is usually mild, with symptoms lasting a few days.

(Source: World Health Organisation)

How to avoid it

To stop yellow fever mosquitoes from breeding, spray in and around your home in dark hiding places with an ordinary surface or cockroach insect spray and tip out or remove anything holding water in your yard.