Two doses of either Pfizer-BioNTech or Oxford-AstraZeneca vaccines provided a similar level of protection to prior natural infection when the Delta variant was dominant.
Effectiveness of two doses remains at least as great as protection afforded by prior natural infection.
https://www.ons.gov.uk/peoplepopulation ... ctober2021
https://www.medrxiv.org/content/10.1101 ... 21262237v1