Video report by ITV News Science Editor Tom Clarke
Almost four in five of all over-80s in the UK have been vaccinated for coronavirus, the health secretary has said, keeping Britain on track to reach its target of inoculating those most vulnerable to Covid-19 by mid-February.
Matt Hancock, speaking at a Downing Street press conference, said 6.6 million people had received a first dose of Covid-19 vaccine - more than 1 in 9 of the adult population.
He said with 78.7% of all over-80s vaccinated having been vaccinated, 250 more people receiving a dose every minute, the UK is "on track to offer everyone in the top four priority groups a jab by February 15."
Around 2.5 million people received their first vaccine last week - the government says it must vaccinate 2 million a week to reach its mid-February target.
But Covid-19 strategic response director at Public Health England, Dr Susan Hopkins, said the UK was still "far away" from achieving herd immunity.
She said: "The big job here is to roll out the vaccination to those individuals first of all, to those who are high risk of death and hospitalisation and then to the rest of the population.
"Once we have done that, then we will have herd immunity."
There's pressure on the government to force arrivals to the UK to spend their quarantine period in hotels, amid concerns over foreign variants of the virus, particularly strains identified in South Africa and Brazil, could be resistant to vaccines.
Hancock said it is "reasonable to take a precautionary principle" to protecting the nation, when asked about introducing quarantine hotels.
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The PM earlier said ministers were “definitely looking at” the possibility of quarantine hotels.
He told reporters: "We have to realise there is at least the theoretical risk of a new variant that is a vaccine-busting variant coming in, we’ve got to be able to keep that under control."
But at least one of the UK's coronavirus vaccines - the Moderna jab - are effective against the new UK and South African variants of Covid-19.
Stéphane Bancel, Moderna's Chief Executive said scientists there are "encouraged" by new data, which "reinforce our confidence that the Moderna Covid-19 Vaccine should be protective against these newly detected variants".
Mr Hancock said scientists in the UK are "doing significant work" to ensure the vaccination programme can be quickly updated if virus mutations become vaccine resistant.
Chief Medical Adviser for NHS Test and Trace, Susan Hopkins said scientists are looking at all variants of coronavirus and will work with the World Health Organisation to see how new vaccines should be built to ensure they protect against new variants, if necessary.
Health Secretary Hancock, asked about a lifting of restrictions, said reaching a decision was "difficult".
"Everybody wants to have a timeline for [lifting lockdown], but I think most people understand why it is difficult to put a timeline on it because it's a matter of monitoring the data, and in fact this is a state-contingent and not a time-contingent question."
He highlighted that there were 37,000 people in hospital with coronavirus, which he said was "almost twice as many as at the first peak back in April".
He also noted there are "more people on ventilators than at any time in this whole pandemic".
The prime minister earlier said ministers would be looking at England's lockdown restrictions ahead of a February 15 review date, but no rule changes will come until after that date.
When England's lockdown was announced, it was hoped schools could reopen following the February half-term if the top four groups most vulnerable groups had been vaccinated.Asked whether schools would open after the February half-term the prime minister said: "We're looking at the data as it comes in, we're looking at the rates of infection, as you know the JCVI groups 1 to 4 are going to be vaccinated by February 15, but before then we'll be looking at the potential of relaxing some measures.
"But don't forget this country has made huge progress in reducing infection, I don't think people want to see another big surge in infection."
It comes after the UK recorded a further 592 coronavirus-related deaths on Monday, bringing the total death toll to 98,531.