The actual paper notes some nuances, particularly one versus two doses (the UK prioritized getting first doses out, so many people got one dose but spent a lot of time in that state waiting for the second dose):
See table 2 on page 17-18.
Two doses of Pfizer - BioNTech resulted in 100% antibody prevalence in ages 18-79, 97.8% in ages 80+. But one dose resulted in antibody prevalence that declined by age from 100% in ages 18-29 to 32.3% in ages 80+.
For the Oxford - AstraZeneca vaccine, two doses resulted in antibody prevalence from 100% in ages 18-39 down to 83.6% in ages 80+, but one dose resulted in antibody prevalence from 72.2% in ages 18-29 to 46.3% in ages 80+.
| Vaccine | 1d vs Alpha | 2d vs Alpha | 1d vs Delta | 2d vs Delta |
|---|---|---|---|---|
| Pfizer - BioNTech BNT162b2 | 49% | 93% | 33% | 88% |
| Oxford - AstraZeneca ChAdOx1 | 51% | 66% | 33% | 60% |
(1d = 1 dose, 2d = 2 doses, Alpha = B.1.1.7, Delta = B.1.617.2)