A research team led by the University of Sydney in Australia will start human trials of a Covid-19 DNA vaccine, the varsity announced on Friday.The gene-based vaccine, developed by Australian biotech company Technovalia and its international vaccine partner BioNet, has been proved safe and effective in preclinical studies, reports Xinhua news agency.With the support from the Australian government, associate professor Nicholas Wood from the University of Sydney will lead the clinical evaluation of the vaccine candidate for the first time in humans."This phase 1 trial will be the first DNA-based Covid-19 vaccine trial in Australia," Wood said.The trial will involve up to 150 healthy participants aged 18 to 75 years old in New South Wales, South Australia and Western Australia to assess the safety, reactogenicity and immunogenicity of different doses of the vaccine."If the trial indicates the vaccine to be safe, then larger phase 2 trials are planned," Wood said.Different from many others, the DNA vaccine will be delivered via a needle-free system."The delivery is via a needle-free device which penetrates the skin with a jet spray," Wood said."This is designed to make sure the DNA vaccine gets inside the cells to encourage good uptake by the immune system."Wood said he expected the trial would officially kick off in November.