More than 600 000 first and second doses of coronavirus vaccine were administered in Britain in the space of 24 hours, according to data released on Saturday.
Official figures showed that 119 306 first doses were given on Friday, and 485,421 second doses.
The data also showed a further 35 people had died from the virus within 28 days of a positive test, and 2 206 people had tested positive.
In the last seven days, daily deaths were down 29% from the previous week, while cases were down 6.5%.
A UK study into using different COVID-19 vaccines in two-dose inoculations is being expanded to include shots made by Moderna and Novavax, researchers said on Thursday.
The trial, known as the Com-Cov study, was first launched in February to look at whether giving a first dose of one type of COVID-19 shot, and a second dose of another, elicits an immune response that is as good as using two doses of the same vaccine.
The idea, said Matthew Snape, the Oxford University professor leading the trial, “is to explore whether the multiple COVID-19 vaccines that are available can be used more flexibly”.
Britain and many other countries in Europe are currently using AstraZeneca’s and Pfizer’s COVID-19 vaccines in nationwide immunisation campaigns against the coronavirus pandemic.
But reports of very rare blood clots have prompted some governments – including France and Germany – to say the AstraZeneca shot should only be given to certain age groups, or that people who have had a first dose of AstraZeneca’s vaccine should switch to a different one for their second dose.
In a briefing about the expansion of the study to include Moderna’s and Novavax’s COVID-19 vaccines, Snape, an associate professor in paediatrics and vaccinology at Oxford, said it will seek to recruit adults aged over 50 who have received their first, or “prime” vaccination in the past 8-12 weeks.