The UK's decision not to prioritise key workers such as teachers or police officers for a Covid jab is "the moral thing to do" and will "save the most lives", the health secretary has said.
More than one in three adults in the UK have now had their first jab.
One of England's top medics said Covid death rates were lower for teachers than several other professions.
Prof Jonathan Van-Tam said ONS data on occupations with the highest Covid death rates begin with restaurant and catering establishment managers or proprietors, followed by metal-working and machine operatives, food, drink and tobacco process operatives, chefs, and taxi and cab drivers.
Speaking at a coronavirus news conference at Downing Street, England's deputy chief medical officer also said the death rates for men in each of these groups were more than 100 deaths per 100,000, compared with 18.4 deaths per 100,000 male teachers.
"When we're getting down into phase two of the vaccine campaigns... being in the queue is more important than where you are in it," Prof Van-Tam added.
The government aims to give a jab to all over-50s and those in specific at-risk groups by 15 April, in what is known as phase one of the UK's Covid vaccine rollout.
It has pledged to complete phase two - where all other adults are offered their first dose - by 31 July.
All four UK nations will follow the approach recommended by the Joint Committee on Vaccination and Immunisation (JCVI).
Mr Hancock said: "Thankfully, teachers are no more likely to catch Covid than any other member of the population who goes to work, and so trying to come up with a scheme which prioritises one professional group over another would have been complicated to put in place and wouldn't have done what we asked the JCVI to do... which is to make sure that we minimise the people who die."
More than 19 million people in the UK have received a first dose so far.
Unions representing teachers and police have criticised the decision.
Dr Patrick Roach, general secretary of the teachers' union NASUWT, said the government was "failing to take all steps possible" to ensure schools remained open "without the risk of further closures or of further damaging disruption to children's education".
John Apter, from the Police Federation, said there was "palpable anger" from officers, adding: "What is expected of policing does put them at risk. It does put them at risk of transmitting this virus."
The next phase of the vaccination programme aimed at the under-50s is all about speed.
The more quickly they can be vaccinated, the more lives can be saved from Covid-19 which reduces pressure on hospitals and makes it more likely the road map out of lockdown can be delivered.
The government's committee of vaccine experts says that means people should be vaccinated according to what age they are and not what job they do.
It would be more complicated and more time-consuming to invite all teachers or police officers for their first dose than to make an offer to all those in their 40s, for example.
Research by the Office for National Statistics suggests a number of occupations have higher-than-average death rates, including restaurant workers, taxi drivers, metal workers and shop assistants - so which group would be prioritised first and how would they be identified?
The conclusion is that a fast, efficient rollout to all adults, by age group, is the best way to achieve the target of giving all adults a first dose by the end of July.
The health secretary also urged people to continue to observe the stay-at-home rules, saying: "We're nearly there - let's not blow it."
Mr Hancock pointed to a range of data that he said showed the pandemic "isn't over yet", including one in five local authority areas seeing a rise in cases in the past week.
Prof Van-Tam also urged people to continue following lockdown rules after receiving a Covid jab.
He said there were "some worry signs" that some people who have had the jab were "relaxing" their compliance with restrictions on socialising.
"It's a bit like being 3-0 up in a [football] game and thinking 'well we can't possibly lose this now'. But how many times have we seen the other side take it 4-3? Do not wreck this now, it is too early to relax," he said.
A further 345 people have died in the UK within 28 days of a positive coronavirus test, according Friday's daily figures, as well as 8,523 new confirmed cases of the virus.
Meanwhile, former Prime Minister Theresa May, 64, has received her first dose of the vaccine.
She said in a tweet that the jab was "effective and painless".
I just had my first Covid-19 jab. It is safe, effective & painless.
When it’s your turn, please #TakeTheVaccine. Only by protecting each other can we defeat this virus.
Thanks to all the brilliant researchers, volunteers, NHS & military personnel for their truly heroic efforts. pic.twitter.com/I74lKRPVlB
The decision not to prioritise COVID-19 vaccinations for groups such as police and teachers has been described as a "deep and damaging betrayal" which "will not be forgotten".
The government has announced people aged 40-49 will be the next in line to get a coronavirus vaccine after all vulnerable groups and the over-50s are covered.
And on Friday, the national chairman of the Police Federation of England and Wales added his opposition.
John Apter told the PA news agency: "There's real palpable anger from all levels within policing about how we have been completely disregarded and ignored in this phase.
More from Covid-19
"What is expected of policing does put them at risk. It does put them at risk of transmitting this virus.
"They're being spat at, coughed at, rolling around on the ground with people, working in hospital environments, going into people's homes. They can't mitigate the risk of the virus.
"All of that means absolutely nothing. This is a very deep and damaging betrayal and it will not be forgotten."
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'Vaccine production is like beer-making'
Paul Whiteman, general secretary of school leaders' union Naht, said school teams "often occupy confined and unventilated spaces for long periods of time with only rudimentary PPE (personal protective equipment)".
"The fact that it may have added some complexity to rollout is not a good enough reason not to prioritise the needs of committed professionals," he said.
"A sick teacher is a teacher away from class, which will mean further disruption to pupils' education and could well mean that they may need to be educated from home again.
"I am amazed by the continuing dedication of school teams. The government has let them down at every turn."
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Evidence jabs cut transmission 'looks good'
In a statement, a government spokesperson confirmed all four nations of the UK would follow the recommendations "subject to the final advice given by the independent expert committee".
The spokesperson added that age had been assessed to be "the strongest factor linked to mortality, morbidity and hospitalisations, and because the speed of delivery is crucial as we provide more people with protection from COVID-19".
Therefore, the priority ordering for phase two will be:
Everyone aged between 40 and 49
Everyone aged between 30 and 39
Everyone aged between 18 and 29
It will begin after all nine priority groups and the over-50s have been offered the jab.
Professor Wei Shen Lim, the COVID-19 chair for JCVI, said age "remains a dominant factor" and that making this a priority would also make the programme more "simple".
He added: "Simplicity has been a cornerstone in terms of speed and success.
"An occupation-based vaccination programme has never been tested; trying to switch will be more complex and potentially introduce more delays into the programme.
"The vaccination programme is a huge success and continuing the age-based rollout will provide the greatest benefit in the shortest time, including to those in occupations at a higher risk of exposure."
Health secretary Matt Hancock told Friday's Downing Street briefing: "Trying to come up with a scheme which priorities one professional group over another would have been complicated to put in place and wouldn't have done what we asked the JCVI to do, which I think is the right thing, which is to make sure we minimise the amount of people who die by using the vaccine."
The decision has been backed by a number of scientists including Jonathan Ball, professor of molecular virology at the University of Nottingham.
He said: "We know that these vaccines are good at protecting from serious disease, and the likelihood of that increases with age.
"Therefore, continuing to target vaccine rollout according to disease risk makes sense, especially if this simplifies the rollout process."
Currently, people in group five of the priority groups - anyone aged 65 and over - are being vaccinated.
Some areas have also moved on to group six - adults aged 16 to 64 with underlying health conditions.
A further 600,000 people who were identified last week as being at additional risk COVID-19 were invited to book a slot at a vaccination centre or pharmacy on Thursday.
Recently, the number of jabs administered has slowed, but Boris Johnson has maintains that all adults in the UK should be offered their first vaccination by 31 July.
He said everyone over 50 should get their offer by 15 April.
Analysis: Too risky to start mass immunisation by profession in the middle of a pandemic
By Ashish Joshi, health correspondent
Keep it simple. Keep it quick. That's the government's vaccination strategy. It's worked so far and there is, as far as the JCVI is concerned, no reason to change it now.
They want as many people vaccinated as soon as possible and the easiest way to do that is to target sections of the population according to age.
By trying to break it down into occupations risks slowing down this monumental effort and undoing all the good work so far.
The mission, right from the very start, is to stop people dying, to stop people becoming very sick and to stop people needed hospital treatment.
The data, say the government's scientists, tells us that is happening. They argue that to move from target age groups to high-risk occupations is too complicated.
And we know that age and underlying health conditions are the two most important factors. The older the patient then the higher the risk from COVID-19. That's why phase one of the rollout targeted the over-50s and the most clinically vulnerable. The next phase will be those aged 40-49.
Another argument is that by hitting this age group you also take in public workers like teachers and police officers who are most at risk by age.
The next phase will start as soon as the first one is over. But significant concerns remain about low vaccine take-up in certain communities like black and Asian; travellers; and Eastern European. The reasons are varied and complex but that is the challenge for public health workers to engage more with these groups and ensure access and counter the misinformation that exists.
This country has never undertaken a mass immunisation programme according to profession. It is too risky to start one in the middle of a deadly pandemic.
Scotland's leadership has "failed", Alex Salmond has told a Holyrood inquiry into the SNP government's unlawful investigation of sexual harassment claims made against him.
The former first minister said Nicola Sturgeon's administration had "acted illegally" in its handling of the allegations, "but somehow no one's to blame".
Mr Salmond told the Scottish Parliament committee "this inquiry is not about me", but about the "unacceptable conduct" around the handling of complaints against him.
He also accused his successor Ms Sturgeon of using a COVID-19 press conference to "effectively question the result of a jury".
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And he claimed the committee in its inquiry had been "systematically deprived of the evidence it has legitimately sought" and had been asked to do its job "with both hands tied behind its back and a blindfold on".
Mr Salmond is testifying on the botched government investigation, which was found to be "tainted by apparent bias" after it emerged the investigating officer had prior contact with two of the women who made complaints.
More from Alex Salmond
He told MSPs: "I have no incentive or advantage in revisiting the hurt and shock of the last three years. For two years and six months, this has been a nightmare.
"I have every desire to move on, to turn the page, to resist talking yet again about a series of events which have been amongst the most wounding that any person can face.
"But the reason I am here today is because we can't turn that page, nor move on, until the decision-making which is undermining the system of government in Scotland is addressed."
He said the failures of leadership surrounding the investigation into his conduct were "many and obvious".
"The government acted illegally but somehow nobody is to blame," he added.
"Scotland hasn't failed, its leadership has failed.
"The importance of this inquiry is for each and every one of us to help put this right."
Hitting out at his former political colleague, Mr Salmond said: "I watched in astonishment on Wednesday when the first minister of Scotland - the first minister of Scotland - used a COVID press conference to effectively question the results of a jury."
Mr Salmond went on: "I note that the first minister asserts I have to prove a case, I don't. That has already been done. There have been two court cases, two judges, one jury.
"In this inquiry it is the Scottish government, a government which has already admitted to behaving unlawfully, who are under examination."
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Salmond 'astonished' at Sturgeon's news briefing
He argued that "some consequences" should follow on from "unlawful conduct".
"I think the leadership of these institutions have serious questions to answer," he told the inquiry.
"When you get to the stage that a government behaves unlawfully - I mean, this is not something that happens very often.
"I'm on the record politically, when governments have behaved unlawfully, of regarding matters a huge and heinous thing to have happened. It's not a slight matter.
"Some consequences should follow from unlawful conduct."
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'A litany of nonsense': Sturgeon in heated exchange
Mr Salmond, who was acquitted of 13 charges of sexual assault in a criminal trial, was awarded a £512,250 payout after he successfully challenged the lawfulness of the government investigation into harassment claims made against him.
Ms Sturgeon has previously insisted there is "not a shred of evidence" that there was a conspiracy against Mr Salmond and she has denied lying to parliament.
The current first minister is scheduled to appear before the committee to give evidence next Wednesday.
Scotland's leadership has "failed", Alex Salmond has told a Holyrood inquiry into the SNP government's unlawful investigation of sexual harassment claims made against him.
The former first minister said Nicola Sturgeon's administration had "acted illegally" in its handling of the allegations, "but somehow no one's to blame".
Please use Chrome browser for a more accessible video player
'Scotland's leadership has failed'
Mr Salmond told the Scottish Parliament committee "this inquiry is not about me", but about the "unacceptable conduct" around the handling of complaints against him.
He also accused his successor Ms Sturgeon of using a COVID-19 press conference to "effectively question the result of a jury".
Advertisement
And he claimed the committee in its inquiry had been "systematically deprived of the evidence it has legitimately sought" and had been asked to do its job "with both hands tied behind its back and a blindfold on".
Mr Salmond is testifying on the botched government investigation, which was found to be "tainted by apparent bias" after it emerged the investigating officer had prior contact with two of the women who made complaints.
More from Alex Salmond
He told MSPs: "I have no incentive or advantage in revisiting the hurt and shock of the last three years. For two years and six months, this has been a nightmare.
"I have every desire to move on, to turn the page, to resist talking yet again about a series of events which have been amongst the most wounding that any person can face.
"But the reason I am here today is because we can't turn that page, nor move on, until the decision-making which is undermining the system of government in Scotland is addressed."
He said the failures of leadership surrounding the investigation into his conduct were "many and obvious".
"The government acted illegally but somehow nobody is to blame," he added.
"Scotland hasn't failed, its leadership has failed.
"The importance of this inquiry is for each and every one of us to help put this right."
Hitting out at his former political colleague, Mr Salmond said: "I watched in astonishment on Wednesday when the first minister of Scotland - the first minister of Scotland - used a COVID press conference to effectively question the results of a jury."
Please use Chrome browser for a more accessible video player
Salmond 'astonished' at Sturgeon's news briefing
Mr Salmond went on: "I note that the first minister asserts I have to prove a case, I don't. That has already been done. There have been two court cases, two judges, one jury.
"In this inquiry it is the Scottish government, a government which has already admitted to behaving unlawfully, who are under examination."
He argued that "some consequences" should follow on from "unlawful conduct".
"I think the leadership of these institutions have serious questions to answer," he told the inquiry.
"When you get to the stage that a government behaves unlawfully - I mean, this is not something that happens very often.
"I'm on the record politically, when governments have behaved unlawfully, of regarding matters a huge and heinous thing to have happened. It's not a slight matter.
"Some consequences should follow from unlawful conduct."
Please use Chrome browser for a more accessible video player
'A litany of nonsense': Sturgeon in heated exchange
Mr Salmond, who was acquitted of 13 charges of sexual assault in a criminal trial, was awarded a £512,250 payout after he successfully challenged the lawfulness of the government investigation into harassment claims made against him.
Ms Sturgeon has previously insisted there is "not a shred of evidence" that there was a conspiracy against Mr Salmond and she has denied lying to parliament.
The current first minister is scheduled to appear before the committee to give evidence next Wednesday.
Scotland's leadership has "failed", Alex Salmond has told a Holyrood inquiry into the SNP government's unlawful investigation of sexual harassment claims made against him.
The former first minister said Nicola Sturgeon's administration had "acted illegally" in its handling of the allegations, "but somehow no one's to blame".
Mr Salmond told the Scottish Parliament committee "this inquiry is not about me", but about the "unacceptable conduct" around the handling of complaints against him.
Please use Chrome browser for a more accessible video player
'Scotland's leadership has failed'
He also claimed the committee in its inquiry had been "systematically deprived of the evidence it has legitimately sought" and had been asked to do its job "with both hands tied behind its back and a blindfold on".
Advertisement
Mr Salmond is testifying on the botched government investigation, which was found to be "tainted by apparent bias" after it emerged the investigating officer had prior contact with two of the women who made complaints.
He told MSPs: "I have no incentive or advantage in revisiting the hurt and shock of the last three years. For two years and six months, this has been a nightmare.
More from Alex Salmond
"I have every desire to move on, to turn the page, to resist talking yet again about a series of events which have been amongst the most wounding that any person can face.
"But the reason I am here today is because we can't turn that page, nor move on, until the decision-making which is undermining the system of government in Scotland is addressed."
He said the failures of leadership surrounding the investigation into his conduct were "many and obvious".
"The government acted illegally but somehow nobody is to blame," he added.
"Scotland hasn't failed, its leadership has failed.
"The importance of this inquiry is for each and every one of us to help put this right."
Mr Salmond went on: "I note that the first minister asserts I have to prove a case, I don't. That has already been done. There have been two court cases, two judges, one jury.
"In this inquiry it is the Scottish government, a government which has already admitted to behaving unlawfully, who are under examination."
He argued that "some consequences" should follow on from "unlawful conduct".
"I think the leadership of these institutions have serious questions to answer," he told the inquiry.
"When you get to the stage that a government behaves unlawfully - I mean, this is not something that happens very often.
"I'm on the record politically, when governments have behaved unlawfully, of regarding matters a huge and heinous thing to have happened. It's not a slight matter.
"Some consequences should follow from unlawful conduct."
Please use Chrome browser for a more accessible video player
'A litany of nonsense': Sturgeon in heated exchange
Mr Salmond, who was acquitted of 13 charges of sexual assault in a criminal trial, was awarded a £512,250 payout after he successfully challenged the lawfulness of the government investigation into harassment claims made against him.
Ms Sturgeon has previously insisted there is "not a shred of evidence" that there was a conspiracy against Mr Salmond and she has denied lying to parliament.
The current first minister is scheduled to appear before the committee to give evidence next Wednesday.
The next phase of COVID vaccinations will continue to prioritise people by age and not their occupation to avoid slowing down the rollout.
People aged 40-49 will be the next in line to get a vaccine after all vulnerable groups and the over-50s are covered, the government said.
The Joint Committee on Vaccination and Immunisation (JCVI) said this would provide "the greatest benefit in the shortest time".
It added that prioritising occupational groups such as teachers and police could make the rollout more complex and could potentially slow the programme overall, leaving some vulnerable people at higher risk for longer.
In a statement, a government spokesperson confirmed all four nations of the UK would follow the recommendations "subject to the final advice given by the independent expert committee".
The spokesperson added that age had been assessed to be "the strongest factor linked to mortality, morbidity and hospitalisations, and because the speed of delivery is crucial as we provide more people with protection from COVID-19".
More from Covid-19
Therefore, the priority ordering for phase two will be:
Everyone aged between 40 and 49
Everyone aged between 30 and 39
Everyone aged between 18 and 29
It will begin after all nine priority groups and the over-50s have been offered the jab.
Professor Wei Shen Lim, the COVID-19 chair for JCVI, said age "remains a dominant factor" and that making this a priority would also make the programme more "simple".
He added: "Simplicity has been a cornerstone in terms of speed and success.
"An occupation-based vaccination programme has never been tested; trying to switch will be more complex and potentially introduce more delays into the programme.
"The vaccination programme is a huge success and continuing the age-based rollout will provide the greatest benefit in the shortest time, including to those in occupations at a higher risk of exposure."
She pointed out that 147 of her colleagues in London alone had been coughed at, while another 51 had been spat at by people claiming to have COVID-19.
Speaking for her colleagues, she added: "They are at a particular risk because of the way in which they are so often going from house to house, in people's personal space, dealing with people who are spitting... this is a many times a day occurrence for my people.
"And inevitably they are concerned that they may take that home, or that they may be spreading as well."
Currently, people in group five of the priority groups - anyone aged 65 and over - are being vaccinated.
Some areas have also moved on to group six - adults aged 16 to 64 with underlying health conditions.
A further 600,000 people who were identified last week as being at additional risk from COVID-19 were on Thursday invited to book a slot at a vaccination centre or pharmacy.
While the number jabs administered has slowed recently, Boris Johnson has said all adults in the UK should be offered their first vaccination by 31 July.
He said everyone over 50 should get their offer by 15 April.
Analysis: Too risky to start mass immunisation by profession in the middle of a pandemic
By Joshi Ashish, health correspondent
Keep it simple. Keep it quick. That's the government's vaccination strategy. It's worked so far and there is, as far as the JCVI is concerned, no reason to change it now.
They want as many people vaccinated as soon as possible and the easiest way to do that is to target sections of the population according to age.
By trying to break it down into occupations risks slowing down this monumental effort and undoing all the good work so far.
The mission, right from the very start, is to stop people dying, to stop people becoming very sick and to stop people needed hospital treatment.
The data, say the government's scientists, tells us that is happening. They argue that to move from target age groups to high-risk occupations is too complicated.
And we know that age and underlying health conditions are the two most important factors. The older the patient then the higher the risk from COVID-19. That's why phase one of the rollout targeted the over-50s and the most clinically vulnerable. The next phase will be those aged 40-49.
Another argument is that by hitting this age group you also take in public workers like teachers and police officers who are most at risk by age.
The next phase will start as soon as the first one is over. But significant concerns remain about low vaccine take-up in certain communities like black and Asian; travellers; and Eastern European. The reasons are varied and complex but that is the challenge for public health workers to engage more with these groups and ensure access and counter the misinformation that exists.
This country has never undertaken a mass immunisation programme according to profession. It is too risky to start one in the middle of a deadly pandemic.