Homeless people and rough sleepers will be prioritised for COVID vaccines, the government has announced.
Health Secretary Matt Hancock confirmed the move after accepting a recommendation by the Joint Committee on Vaccination and Immunisation (JCVI).
It means the homeless and rough sleepers will be given jabs alongside priority group 6 in the UK's vaccination programme, who are those aged between 16 and 65 with underlying health conditions.
So far, more than 23 million people in the UK have received a first vaccine dose.
In a letter to Mr Hancock earlier this month, the JCVI's Professor Wei Shen Lim said the homeless and those sleeping rough "have a higher risk of poorer outcomes of COVID-19 compared to the general population".
He said the housing of thousands of rough sleepers in emergency accommodation during the pandemic had provided a "unique opportunity" to offer vaccines to those who were otherwise often unable to access basic healthcare.
"Having noted that many homeless individuals are likely to have underlying health conditions which would place them in group 6 of the first phase of the programme and that these conditions are likely to be under-diagnosed or incompletely recorded in primary care records," Prof Lim, who is the JCVI's COVID chair, wrote.
"JCVI advises that local teams exercise operational judgment and consider a universal offer to people experiencing homelessness and rough sleeping, alongside delivery of the programme to priority group 6, where appropriate."
He also highlighted how some areas had already decided to prioritise rough sleepers for vaccines.
The JCVI advised that first doses should be offered to these groups even without the need for an NHS number or registration with a doctors' surgery.
They added that, although the optimal timing for a second dose of the Oxford/AstraZeneca vaccine is eight to 12 weeks after the first dose, local officials may decide on a shorter schedule for those who might be unlikely to return for a follow-up jab.
The letter also asked those providing shelter to consider the "benefit for access to stable accommodation with respect to the timely delivery of two doses of the COVID-19 vaccine".
Confirming he had accepted the JCVI's recommendation, Mr Hancock said: "Our vaccination rollout is moving at an incredible speed with two in every five adults now having received at least one vaccine.
"It's so important that nobody gets left behind in this national effort.
"We know there are heightened risks for those who sleep rough and today I have accepted the advice of the independent experts at the JCVI to prioritise those experiencing rough sleeping or homelessness for vaccination alongside priority group 6.
"This will mean we will save more lives, among those most at risk in society."
Jon Sparkes, chief executive of the homelessness charity Crisis, welcomed the move and said it is vital homeless people can access the vaccine "as quickly as possible".
"The UK government must now ensure that, working with homelessness services, all local areas have the resources they need to make this happen," he added.
"But make no mistake, the vaccine will not make homelessness safe.
"Whether it is living on the streets, or in cars and sheds, or constantly moving between friends' sofas, homelessness is extremely damaging to both your physical and mental health.
"We desperately need a plan to ensure everyone has a safe and secure home."