The UK passed the milestone of 10m second doses on 18 April - meaning nearly one in five of all UK adults have now received two doses of COVID-19 vaccine.
Government figures show that by the end of Saturday 17 April, 9,930,846 people UK-wide had received two doses of vaccine. More than 350,000 second doses were delivered per day on average over the week to 17 April - and the daily total has dropped below 200,000 just once in the past 12 days - suggesting that the 10m mark was passed over the weekend.
Despite fears that first-dose vaccinations would come to a near standstill through April after the government warned that supplies of vaccine would 'dry up', 1.7m first-dose vaccinations were administered UK-wide between 1 and 17 April - 24% of the 7.1m total so far this month.
UK-wide, a total of 42.8m doses of COVID-19 vaccine have now been administered in total, including 32.8m first-dose vaccinations - 77% of the total.
Figures for England suggest that around nine in 10 people aged over 50 have now had a first dose of COVID-19 vaccine, and nearly one in four have received two doses.
Across England, 19,952,918 first-dose jabs and 5,061,087 second doses had been administered by 11 April to people aged over 50. Based on population data from the National Immunisation Management Service, this equates to around 89% of all over 50s given one dose, and 23% both doses.
Dr Susan Hopkins, medical adviser to the government's track and trace programme, told the BBC's Andrew Marr programme on 18 April that some cases of COVID-19 infection had continued to be found in patients who had received doses of vaccine.
She said this was 'to be expected' because vaccines did not offer 100% protection against infection - but she said that it was very likely that hospitalisation and death would be largely stopped in vaccinated patients.
Dr Hopkins said cases of community transmission of the South Africa variant of the virus had been seen mostly in urban areas - and most significantly in south London, where surge testing has been rolled out.
She said limited data available suggested that vaccines were 'not as good' at preventing infection and transmission of the South Africa variant as they were in stopping variants more prevalent in the UK.
A small number of cases of transmission of the Indian variant of the virus had also occurred in the UK, Dr Hopkins said - but data to determine whether the variant caused increased severity of disease, increased transmissibility or was vaccine evading was as yet unavailable.