https://www.theguardian.com/world/2020/nov/26/scrutiny-grows-over-oxford-universityastrazeneca-vaccine

Share price drops as critics question claim vaccine could protect up to 90% of people

The Oxford University/AstraZeneca vaccine will undergo a new global trial as critics questioned the claim that it could protect up to 90% of people against coronavirus.

https://www.afr.com/companies/healthcare-and-fitness/astrazeneca-to-run-fresh-covid-19-vaccine-trial-amid-results-confusion-20201127-p56igq