The outcome will be determined using data from the UK government (Coronavirus.data.gov.uk). See "Vaccination uptake, by report date," and select "UK Total." If the UK government changes how it reports vaccination data (e.g., including the administration of single-dose vaccines), we will provide clarifying language as necessary (BBC). As of 2 June 2021, full course uptake in the UK was 50.7%.

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NOTE 19 August 2021: After reviewing the changes that were made to the data available on the cited source, we have determined that we cannot use it directly to resolve the question. With figures reflecting all of those with a 2nd Dose regardless of age, we cannot adjust for the change in the denominator directly. However, after contacting the UK Coronavirus Dashboard team, we have found underlying sources which are substantively the same as the one referenced to initially, enabling us to keep this question open.

We were able to verify the 18 and over 2nd Dose vaccination figures by using data from the public health services of all four countries in the UK, which are the sources of data used by the initial resolution source. The links to the sources for England, NI, Scotland, and Wales are below this note.

We will be using these data for resolution. As of today, 19 August 2021, the total number of persons 18 and over having received a 2nd Dose was 40,960,540. Moreover, the reference number being used by the source for 18 and over population in the UK is 52,890,044, per communication from the UK Coronavirus Dashboard team and the UK's Office for National Statistics. This means that 42,312,036 is the threshold that must be crossed for resolution, adding the number from all 4 countries in the UK.

We apologize for the change, but it is necessary to keep the question open, considering changes in initial sourcing.

Data from each country in the UK:

NHS England: https://www.england.nhs.uk/statistics/statistical-work-areas/covid-19-vaccinations/, see "Data" and file sheet "Vaccinations by LTLA and Age"

NHS Scotland: https://public.tableau.com/app/profile/phs.covid.19/viz/COVID-19DailyDashboard_15960160643010/Overview#!/vizhome/COVID-19DailyDashboard_15960160643010/Overview

NHS Northern Ireland: https://covid-19.hscni.net/ni-covid-19-vaccinations-dashboard/, see slide 4 of 6

NHS Wales: https://public.tableau.com/app/profile/public.health.wales.health.protection/viz/RapidCOVID-19virology-Public/Headlinesummary, click "Vaccination" in the gray ribbon near the top

The question closed "Between 1 August and 31 August 2021" with a closing date of 28 August 2021.

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