By the end of 28 January, 7,891,184 people UK-wide had received at least one dose of COVID-19 vaccine, according to government figures - just over halfway to the mid-February target.
With just over two weeks to go, the task of completing first-dose vaccinations for all 15m people UK-wide in the first four priority cohorts identified by the Joint Committee on Vaccination and Immunisation (JCVI) remains daunting, however.
To hit the target by 15 February, vaccination sites across the UK will need to deliver more than 400,000 doses a day - a mark that has only been achieved on four days since the vaccination programme began in December.
COVID-19 vaccination data for the UK show a marked acceleration in doses administered on 28 January compared with the previous day, however, with 443,985 people given a first dose - up 57% from the previous day's total.
In England a total of 341,127 first doses were administered on 28 January - 37% up from the previous day.
Data published by NHS England show that by 24 February four in five patients aged over 80 had received at least one dose of vaccine - although progress is varied across the country.
London has made more progress than other areas over the past two days - but was surpassed by several other regions on 28 January in terms of daily vaccinations administered.
Three types of COVID-19 vaccine have now been approved for use in the UK by the MHRA - the Pfizer/BioNTech, Oxford/Astra Zeneca and Moderna vaccines - and promising trial data on two further products have emerged in the past 24 hours.
Ministers have insisted they expect to achieve the mid February target set out in a vaccine delivery plan earlier this month - but have warned repeatedly that supply of vaccine remains the 'rate-limiting factor' for the UK vaccination campaign.
Primary care networks will begin to receive the first payments for vaccinations delivered through the COVID-19 vaccination enhanced service towards the end of February.