Human trials of potential coronavirus vaccine begin in Melbourne

Phase 1 trials mostly concern themselves with measured antibody response, adverse effects, etc. They're not actually testing for efficacy against the vaccine in the wild yet, because the sample size is too small. They're testing it on 130 people so that for phase 2 they can be reasonably certain when they give it to several thousand people that there won't be unmanageable risks.

From McGraw-Hill Concise Dictionary of Modern Medicine:

Phase I Early clinical stage Phase I studies are designed to examine the safety of a new medication and understand how it will work in humans by gathering extensive data on how it is absorbed, distributed, metabolized and eliminated from the human body; other data include assessment of how quickly therapeutic concentrations is achieved, how long the drug remains in the body, and what, if any, the effect drug metabolite by-products may have; with step-by-step increases in dose, the optimal dosage is determined where minimum side effects are coupled with maximum therapeutic effect, termed the toxic-therapeutic window; a trial to determine the best way to give a new treatment and what doses can be safely given; phase 1's involve 20-80 subjects and generate data on toxicity and maximum safe dose, to later allow a properly controlled trial.

Phase 2 Later clinical stage Phase 2 studies are designed to evaluate the short-term therapeutic effect of a new drug in Pts who suffer from the target disease,

From the OP:

Dr Glenn said vaccine availability was a "very complex issue" but said the company was "committed to global access", which was why phase two trials would take place with thousands of volunteers in different countries.

They must be testing some aspect of the vaccine that doesn't require exposure to the virus.