US-based Inovio Pharmaceuticals has begun its second clinical study of its Zika vaccine, GLS-5700 in Puerto Rico, which has declared Zika virus outbreak as a public health emergency.

The company is developing its preventive Zika vaccine, GLS-5700, in collaboration with GeneOne Life Science and other academic collaborators from the US and Canada.

GLS-5700 has been designed to offer broad protective antibody and trigger therapeutic T-cell responses against a range of Middle East respiratory syndrome (MERS) viruses, including the Zika virus.

The placebo-controlled, double-blind trial has involved 160 healthy adult volunteers from Puerto Rico, who will be divided into two groups of 80 subjects to be treated with GLS-5700 and Inovio’s CELLECTRA 3P device and placebo.

"Inovio and its collaborators are moving ahead with this second Zika vaccine clinical trial to evaluate safety, immune responses, and possible signals of vaccine efficacy."

The trial intends to determine the safety, tolerability and immunogenicity of the Zika vaccine.

Inovio president and CEO Dr Joseph Kim said: “The rapid progression of the Zika outbreak in Puerto Rico provides an immediate and unique opportunity to assess a preventive vaccine in a real world setting.

“Inovio and its collaborators are moving ahead with this second Zika vaccine clinical trial to evaluate safety, immune responses, and possible signals of vaccine efficacy.

“If the results are promising, we plan to meet with regulators in 2017 to map out the most efficient path forward to develop our Zika vaccine and help mitigate this widespread Zika outbreak that has expanded into the continental United States.”

Preclinical tests conducted on large and small animal models demonstrated the vaccine’s ability to induce robust antibody and T-cell responses to fight viral infections.