The potential vaccine is already in large-scale Phase III human trials to assess whether it can protect against Covid-19, but its developers have yet to report Phase I results which would show whether it is safe and whether or not it induces an immune response.

from Times of India https://timesofindia.indiatimes.com/world/uk/positive-news-on-oxford/astrazeneca-covid-19-vaccine-could-come-today-report/articleshow/76992478.cms