As of August 2017, Sanofi discontinued development for Zika virus vaccine in the US and Puerto Rico because the Biomedical Advanced Research and Development Authority decided to de-scope its contract with Sanofi to fund the manufacture and clinical development of an inactivated Zika vaccine. In addition, Sanofi does not intend to continue development of, or seek a license from, the Walter Reed Army Institute of Research for the Zika vaccine candidate  .
Sanofi Pasteur and the the Walter Reed Army Institute of Research (WRAIR) had initiated phase I trials [see below] for Zika virus vaccine sponsored by National Institute of Allergy and Infectious Diseases (NIAID)   .
Results from the three phase I trials NCT02963909, NCT02952833 and NCT02937233 [see below] released by Walter Reed Army Institute of Research in December 2017, showed that Zika purified inactivated virus vaccine induced robust immune response  .
In October 2018, NIAID completed a phase I trial designed to evaluate the safety, reactogenicity and immunogenicity of two doses of alum adjuvanted Zika virus purified inactivated vaccine (ZPIV) in healthy flavivirus-naïve and flavivirus-primed (YF-VAX® and IXIARO®) volunteers (16-0062; NCT02963909). The randomised, double-blinded, parallel study was initiated in November 2016 and recruited 75 volunteers in the US  .
In October 2016, NIAID initiated a phase I trial to evaluate the safety, reactogenicity and immunogenicity of alum adjuvanted ZPIV in a homologous prime-boost regimen to healthy flavivirus-naïve volunteers (16-0033; HHSN272200800003C; NCT02952833). The randomised, double-blinded, placebo-controlled, dose de-escalation, parallel study is designed to enrol 90 volunteers in the US  .
In June 2018, Beth Israel Deaconess Medical Center completed the Z001 phase I trial designed to evaluate the safety and immunogenicity of an accelerated vaccination schedule with a Zika virus purified inactivated vaccine plus alum adjuvant in healthy volunteers (2016P000268; NCT02937233). This placebo controlled, double-blind, randomised trial was initiated in October 2016 and enrolled 36 volunteers in the US  .
NIAID initiated a phase I trial to evaluate the safety, reactogenicity and immunogenicity of alum adjuvanted ZPIV administered to healthy male and non-pregnant female adult volunteers (16-0034; HHSN272201300021I; NCT03008122). The randomised, double-blinded, placebo-controlled, dose de-escalation, parallel study is designed to enrol 90 volunteers in Puerto Rico  .
Preclinical results demonstrated that an immune response was generated by single dose of Zika virus vaccine, which protected mice from subsequent Zika challenges, with Brazilian strain of virus  . In February 2016, Sanofi Pasteur initiated a research and development programme to develop a vaccine candidate for the prevention of Zika virus infection  .