Biotech drug developer Vical Inc. has announced that its pandemic bird flu vaccine candidate Vaxfectin was safe and effective in an early clinical trial, reports Forbes.

Vaxfectin was tested on about 100 patients in the proof-of-concept study. Vical said the vaccine caused antibody formation and T-cell responses against the H5N1 strain of the virus.

There was evidence of antibody responses in 67% of subjects when the vaccine was given in high doses, the company said.

Vical also said that the responses persisted 6 months through the end of the study, which suggests the vaccine could provide long-lasting protection. Vaxfectin may also provide protection against other strains of the influenza virus, it added.