The UK Office for National Statistics actually puts out estimates for the prevalence of covid antibodies (from both vaccines and infections combined), and you a

The UK Office for National Statistics actually puts out estimates for the prevalence of covid antibodies (from both vaccines and infections combined), and you are right on the money! They estimated that as of June 14, 89.8% of the population would test positive for antibodies. https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveyantibodyandvaccinationdatafortheuk/7july2021 https://www.ons.gov.uk/peoplepopulationandcommunity/healthan... Indeed, even with Delta’s terrifying R-value, this seems like enough to suppress the virus.