A phase 1 vaccine study including 195 people was published in May that shows the vaccine is safe. Even better, another phase 1 study of 1000 people in the UK also suggests the vaccine is safe [report not yet published]. We can infer this though because they’ve now launched the phase 2/3 trial. This would only be possible if the phase 1 study showed it was indeed safe. The phase 2/3 trial started a few days ago, and they will be testing the effectiveness of the vaccine in over 10,000 people.