- Coronavirus pandemic
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It "makes sense" for people who have been fully vaccinated to be treated differently to those who are not, Health Secretary Sajid Javid has said.
He will make an announcement later on self-isolation changes in England for those who have had both Covid jabs.
He also said daily cases "could go as high as 100,000" when restrictions were fully lifted.
And the government will give more details later on how it plans to relax Covid rules for schools in England.
The "bubble" system has led to large numbers of pupils being sent home if a single child has a positive test.
On Monday, the prime minister confirmed he intended to scrap most of the remaining restrictions in England on 19 July, including the laws on mask wearing and rules on social distancing.
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Mr Javid told BBC Radio 4's Today programme he would expect cases numbers by 19 July to be "at least double" what they were now "so around 50,000 new cases a day".
"As we ease and go into the summer we expect them to rise significantly and they could go as high as 100,000 case numbers," he added.
However, he said vaccines and treatments "are far better than what we had when this pandemic began" resulting in a much lower fatality rate.
Asked whether he would end the need to self-isolate for those who have had both vaccine doses, Mr Javid said: "It makes sense because of the vaccines, and the way they're working, that the people that are double vaccinated are treated differently than the people that are not, and that is what I will be saying in Parliament today."
People identified as close contacts of a confirmed Covid case are currently required to self-isolate for up to 10 full days when contacted by NHS Test and Trace.
media captionSajid Javid: "I will continue to carry a face mask with me for the foreseeable future"
Other changes announced on Monday include the planned reopening of nightclubs for the first time since the pandemic began, an end to all legal limits on the number of people who can attend events, and the scrapping of guidance to work from home.
Mr Javid said the UK was now entering "uncharted territory" as it moved to lift legal restrictions – but he said the decision had to be made because of the "other health problems" facing millions of people who didn't receive treatment during the pandemic.
Asked about whether he would keep wearing a mask, he said he would carry one for the "foreseeable future" and would wear one in a crowded or enclosed space, adding that he hoped others would do the same.
Prof Neil Ferguson, from Imperial College – whose modelling helped lead to the first nationwide restrictions – said as restrictions eased there was the potential for the UK to have a very large numbers of cases – 150,000 to 200,000 a day – which could "still cause some pressure to the health system".
However he told BBC Radio 4's Today programme that although it was a "slight gamble" he thought it was "justifiable", adding "I'm reasonably optimistic."
He said the vaccines would keep deaths far lower than in previous waves. "The ratio which we saw in the past between case numbers and deaths has been reduced by more like eight to 10-fold."
He said that in the worst-case scenario there "may need to be a course correction later".
The planned relaxation of restrictions on 19 July is essentially an acknowledgement the government is now happy to let Covid spread, in the knowledge the most vulnerable have a good level of protection.
But it is also being done with the expectation that, at some point, cases will begin to plateau as the virus hits the wall of immunity built up by the vaccination programme and natural infection.
That may not happen before we hit 50,000 cases a day, perhaps even 100,000, which of course would mean lots of people having to quarantine because they come into close contact with someone who is infected.
There are already reports of hospitals being short of staff because doctors and nurses are self-isolating because they are classed as a close contact.
And this is being mirrored in workplaces and other settings across the country. If allowed to continue, the country is at risk of grinding to a halt this summer.
For people who have been doubled jabbed, the chances are they will not become infected – the vaccines offer about 80% protection against symptomatic infection.
As always with Covid, it comes down to what is proportionate.
Labour politicians, as well as some doctors and trade unions, have expressed concern that the lifting of the restrictions may be premature.
Shadow health secretary Jonathan Ashworth said although he was "in favour of reopening our economy", he felt there was a need to maintain a legal requirement to continue wearing masks in shops and on public transport.
He said it was "peculiar" to have a situation where more people would be getting on trains and buses while telling them they didn't have to wear a mask anymore.
Businesses have given mixed reactions to the prime minister's latest announcement.
Melvin Benn, chief executive of Festival Republic, which runs the Reading and Leeds festivals, said the government had "got this right", adding that "the country wants to reopen, we are tired of this, we want to reopen".
He also said he was not inclined to encourage festival guests to wear masks – even indoors.
However, Jacinta Rowsell, manager of the Westfield shopping centre in London, said staff would still "encourage guests" to wear masks as they wanted people visiting to feel safe.
She added that each retailer in the centre "may implement their own policy" on mask wearing inside their stores.
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Scotland, Wales and Northern Ireland are in charge of their own coronavirus rules.
The Scottish government has said it may continue to require masks in certain settings even after 9 August, when it is hoped the final curbs will end.
Ahead of a review on 15 July in Wales, ministers said people would need to learn to live with Covid. Rules in Northern Ireland have just eased, with another review due on 8 July.
On Monday, a further 27,334 cases were reported across the UK – and another nine deaths within 28 days of a positive test.
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