For this interested in the actual science this is the original article: Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant
Information on the data source:
Data on all persons in England who have been vaccinated with Covid-19 vaccines are available in a national vaccination register (the National Immunisation Management System). Data regarding vaccinations that had occurred up to May 16, 2021, including the date of receipt of each dose of vaccine and the vaccine type, were extracted on May 17, 2021.
Even more interestingly:
The three data sources described above were linked with the use of the National Health Service number (a unique identifier for each person receiving medical care in the United Kingdom). These data sources were also linked with data on the patient’s date of birth, surname, first name, postal code, and specimen identifiers and sample dates … Surveillance of coronavirus disease 2019 (Covid-19) testing and vaccination is undertaken under Regulation 3 of the Health Service (Control of Patient Information) Regulations 2002 to collect confidential patient information (www.legislation.gov.uk/uksi/2002/1438/regulation/3/made. opens in new tab) under Sections 3(i) (a) to (c), 3(i)(d) (i) and (ii), and 3.
So, this is all Covid-19 vaccine patient data up to May 16, 2021 from England, UK exclusively.
Note the UK overall uses a different schedule for the Pfizer vaccine distribution. Instead of 21 days, as per the manufacturer, it is 8-12 weeks – excluding relatively recent walk-in vaccine center distribution which can lower that, but still likely remains well beyond the 21 days. Other science, e.g. Extended interval BNT162b2 vaccination enhances peak antibody generation in older people (a small study), has show increased antibody effectiveness from an extended schedule.