The UK vaccines taskforce has bought a further 60m doses of the Pfizer/BioNTech vaccine - in addition to 40m doses already lined up for the UK.
Of the three vaccines currently approved for use in the UK, the taskforce has now secured access to 100m doses of the Pfizer/BioNTech vaccine, 100m doses of the Oxford/AstraZeneca vaccine and 17m doses of the Moderna vaccine.
Health and social care secretary Matt Hancock said earlier this month that the government was 'ramping up' plans for a COVID-19 booster campaign that will go ahead from autumn.
More than a quarter of the UK adult population has now received two doses of COVID-19 vaccine, around four and a half months since the first jab was administered in December.
GP-led vaccination sites have delivered more than three quarters of COVID-19 jabs in England - and participation in the campaign has placed intense pressure on general practice, alongside the impact of what NHS England has described as 'pent-up demand' after more than a year affected by the pandemic.
Running the COVID-19 booster campaign alongside this year's flu vaccination campaign - which has been expanded to cover people aged 50-64 in addition to the usual at-risk groups for a second year - could pose a huge challenge for general practice, particularly if the jabs cannot be administered together.
Mr Hancock told MPs earlier this year that the government was awaiting 'final clinical results on their interaction to see whether someone can have both at the same time, which would obviously be logistically easier'.
COVID-19 vaccine impact
Evidence from Public Health England (PHE) suggests that the vaccination programme had saved around 10,400 lives among people aged over 60 by the end of March.
A PHE report has also shown that vaccination can reduce the risk of household transmission of COVID-19 by up to half. The study showed that people who become infected three weeks after receiving a single dose of Pfizer/BioNTech or Oxford/AstraZeneca vaccine were 'between 38% and 49% less likely to pass the virus on to their household contacts'.
People who have been vaccinated are also 60-65% less likely to become infected in the first place from four weeks after a single dose of either vaccine.
Mr Hancock said new variants of coronavirus remained the 'biggest risk' to progress on easing lockdown restrictions across the UK.
He said: 'We're working on our plans for booster shots, which are the best way to keep us safe and free while we get this disease under control across the whole world.
'These further 60m doses will be used, alongside others, as part of our booster programme from later this year, so we can protect the progress that we’ve all made.'
The government will publish further details on the booster programme in due course and the final policy will be informed by advice from the Joint Committee on Vaccination and Immunisation (JCVI) and the results of clinical trials studying the use of different combinations of approved Covid-19 vaccines.
The government has said that full details of the booster campaign will be published 'in due course' based on advice from the Joint Committee on Vaccination and Immunisation.
A total of 47.5m doses of COVID-19 vaccine had been administered UK-wide by the end of 27 April, including 34m first doses, and 13.6m second doses.