You might be interested to know that a new report from Public Health England on a giant observational study of 300k plus vaccinated people, broken down by age and type of vaccine, basically confirmed your guesstimate numbers to within a few percent (VE for Pfizer 2 dose Vs Delta is about 85% and wanes such that it about halves in efficacy after 100 days, and is twice as good in younger age groups). They even have nice graphs showing efficacy over time,
You might be interested to know that a new report from Public Health England on a giant observational study of 300k plus vaccinated people, broken down by age and type of vaccine, basically confirmed your guesstimate numbers to within a few percent (VE for Pfizer 2 dose Vs Delta is about 85% and wanes such that it about halves in efficacy after 100 days, and is twice as good in younger age groups). They even have nice graphs showing efficacy over time,
Thread summary: https://twitter.com/john_actuary/status/1428269230798123008?s=20
Actual paper: https://t.co/9NtGXNHyKW?amp=1