Immunization, Vaccines and Biologicals

Zika virus vaccine product development

Background

Zika virus disease is caused by a virus, belonging to the Genus Flavivirus, that is transmitted mainly by Aedes mosquitoes. While mostly causing only mild illness, the virus has in recent outbreaks been associated with severe complications, such as Guillain-Barré syndrome and congenital neurological abnormalities in infants born to mothers having experienced Zika virus infection during pregnancy.

In mid-2016, WHO in collaboration with UNICEF and a working group of independent subject matter experts developed a Zika virus vaccine target product profile (TPP) for use in an emergency, or in a future outbreak scenario. This TPP was revised in February 2017 taking into consideration new data that emerged since the original document was published.

The drafting process of the Zika virus vaccine TPP included a public consultation through online posting, as well as a meeting with stakeholders to consider the regulatory expectations and potential emergency use pathways for a vaccine with the characteristics described in the TPP. A second online public consultation was held for the revised TPP.

On January 10-11, 2017, US NIAID and WHO cohosted a Scientific Consultation on Zika Virus Vaccine Development that provided a state-of -science review on Zika epidemiology and vaccine development.

On June 1-2, 2017, the WHO convened a group of about 30 experts in epidemiology, regulatory, preclinical and clinical vaccine trials, and mathematical modelling, in a workshop on planning for Zika vaccine efficacy trials.

The workshop aimed to define generic principles on how to best design, conduct and analyze vaccine trials against ZIKV, based on the best available scientific evidence as well as on lessons learned from evaluating other flavivirus vaccines.

WHO continually monitors the progress of ZIKV vaccine candidates. The WHO vaccine pipeline tracker includes non-clinical and clinical candidates under active development based on the latest information.