Japanese drugmaker Takeda Pharmaceutical has secured funding from the US Biomedical Advanced Research and Development Authority, BARDA, part of the US Department of Health and Human Services, for its ongoing effort to develop a vaccine to prevent Zika, the virus linked to severe birth defects such as microcephaly and severe fetal brain abnormalities.

The funding arrangement could be worth as much as $312 million if the agency finds the vaccine worthy of moving through late stage testing and filing for approval, Takeda said. Initially, the company, which is also working on vaccines for other mosquito-borne viruses such as dengue, said will receive nearly $20 million to fund pre-clinical research and manufacturing in preparation for early human trials.

Takeda has been conducting preclinical testing with a vaccine for several months and hopes to begin Phase 1 trials in healthy volunteers in the second half of 2017, Rajeev Venkayya, head of global vaccines, told the news agency Reuters.  The company said it is also in discussions with the Japanese government on its possible participation in the Zika collaboration.

According to Venkayya, the Japan-developed vaccine will utilize inactivated whole Zika virus to promote an immune response. Other vaccines now in early human testing are DNA-based and contain no actual virus, he said.

A number of other pharmaceutical producers companies and US government agencies are involved in efforts to develop a safe and effective vaccine against the virus that has spread across the Americas since the current outbreak was detected in Brazil in 2105. It was recently announced that Inovio Pharmaceuticals and the US National Institutes of Health have begun human trials of vaccine candidates.

US authorities are stepping up the effort to find a vaccine after it became apparent that local mosquitoes were transmitting the Zika virus in an area of south Florida. The US territory of Puerto Rico has also experienced a widespread outbreak, along with, more recently, Singapore. The World Health Organization officials said the spread of the virus into Asia makes it a continued global health emergency. Although mosquitoes are the primary mode of transmission, Zika also can be transmitted through unprotected sex with an infected person.