More than a third of care homes in England have now recorded a coronavirus outbreak, official figures reveal.
Public Health England data shows 5,546 care homes out of a total of 15,514 had confirmed or suspected outbreaks since early March and almost every district has now had an outbreak in at least one.
Age UK said the situation in care homes was "a scandal behind closed doors".
The government has promised £600m to control infection in care homes.
More than 9,700 care home residents across the UK have died with Covid-19, according to the Office for National Statistics and its counterparts in Scotland and Northern Ireland.
In England, every local authority area with care homes, apart from the Isles of Scilly, has now reported at least one outbreak.
The number of homes reporting their first outbreak has been dropping, from a peak of 1,002 in the week starting 6 April to 418 in the week starting 4 May.
Caroline Abrahams, from Age UK, said care homes were still struggling to access personal protective equipment (PPE) and testing.
"With every day it becomes clearer that what's been happening in care homes is a scandal behind closed doors and whatever happens we must make sure it can never happen again," she said.
The data shows 354 homes out of 748 in the North East, more than 47%, had recorded an outbreak.
That compares with just over a quarter of homes in the South West.
What are care homes doing to protect people?
Some care homes have revealed how staff have moved in to help shield residents from coronavirus by isolating with them.
Other measures include setting up isolation areas for people being discharged from hospital to stop them potentially bringing Covid-19 into the care home.
Castle Court care home in Castle Gresley and Whitestones in Chapel-en-le-Frith, both run by Derbyshire County Council, have such facilities in place.
Derbyshire County Council said the homes had separate entrances to the rest of the buildings which was minimising the risk of spread.
'Battle knickers on'
For Sarah Ballin and her colleagues, keeping coronavirus out of their care home is like a military operation.
So far, Coxbench Hall in Amber Valley, Derbyshire, has not seen any of its 31 residents or 60 staff contract Covid-19, but keeping things that way involves a lot of effort.
In April, the residents got involved in making PPE for the staff, but since then the home has received donations of scrubs and visors.
Ms Ballin said everyone knows they have a fight on their hands.
"We say we've got our battle knickers on," she said, detailing how the staff take residents' temperatures twice a day, enter anything they notice on handheld computers and take various precautions.
Any time a resident goes to hospital in an ambulance, their room is thoroughly cleaned including with a disinfectant fog.
Today is a beautiful day for....... disinfectant fogging. He’s back again doing an excellent job.Posted by Coxbench Hall Residential Home on Wednesday, May 13, 2020
Health workers are allowed in to one room but must have their temperatures taken before residents are brought to them.
Post and packages are kept for three days and then disinfected before being given to residents to avoid any trace of coronavirus lingering.
"We are struggling to get tests," Ms Ballin said. "Our nearest test centre is in Grantham which is the best part of an hour's drive away.
"But we're all helping each other get through this."
In Rotherham, care homes are being granted £15,000 each by the local council to help them meet the increasing costs of dealing with the pandemic.
Councillor David Roche said care homes were under "significant pressure" from taking on new residents at short notice or quickly re-admitting residents from hospital.
"They are incurring additional costs, increased personal protective equipment (PPE) costs, accepting new residents at short notice, sickness levels," he said, "and due to sickness levels, increased agency costs."
Deputy leader of Peterborough City Council, Wayne Fitzgerald, described the rate of coronavirus infections in care homes as "devastating".
The city's executive director for people and communities, Wendi Ogle-Welbourn, told a cabinet meeting the council was helping care homes with staffing shortages due to care workers self-isolating and would provide emergency supplies to those with less than seven days' stock of PPE.
Ms Ogle-Welbourn said larger homes had created isolated areas for people recovering from coronavirus but smaller homes "may choose to isolate them in the best way that they can".
Kate Terroni, chief inspector of adult social care at the Care Quality Commission, said the watchdog would be "exploring further how organisations manage infection control and what support and resources they have to effectively control the spread of the virus".
"Those who work in social care have never had a more crucial - or a more challenging - role to play," she said. "We are here to support them so they can continue to keep people safe during this global emergency."
Public Health England said it had been "working closely with care homes and the wider social care sector to provide advice and support to them in preventing and managing outbreaks."
On Wednesday the prime minister announced an extra £600m to fight coronavirus infections at care homes in England.
Boris Johnson said the government had brought in the lockdown in care homes ahead of the general lockdown but that there was "unquestionably an appalling epidemic" in that setting but that "the number of outbreaks is down and the number of fatalities well down".
Additional reporting: The Local Democracy Reporting Service