Concerns are growing over an increase in Covid-19 cases in care homes, prompting the government to send an alert to care providers to highlight the rising rates and to call for action.

The letter, which was sent on Friday, urges care bosses to “take the necessary action to prevent and limit outbreaks”, pointing out that in the last three days there had been an increase in notifications of coronavirus cases in care homes.

At the moment it is the workforce that is most affected, but the letter says that “clearly” there is a risk that the virus will spread to residents and in some cases already has.

The letter, which was written by Stuart Miller, director of adult social care delivery at the Department of Health and Social Care, said: “You will know already that we are experiencing a rise in confirmed Covid-19 cases, across the UK population.

“I need to alert you to the first signs this rise is being reflected in care homes too. Over the past three days, Public Health England (PHE) has reported an increase in notifications of Covid-19 cases in care homes.

“Testing data has also shown an increase in the number of positive results. Currently, the infections are mainly affecting the workforce but clearly there is a risk the virus will spread to care home residents, or to other parts of the care sector.

“Unfortunately, in some care homes with recent outbreaks, this does appear to have occurred, with residents also becoming infected.”

The Sunday Times reported a Department of Health report marked “official sensitive” and circulated on Friday said that the rate of coronavirus recorded through satellite tests – which are used in care homes – had quadrupled since the start of the month.

The newspaper also said that Health Secretary Matt Hancock was given an emergency update on Wednesday saying that outbreaks had been detected in 43 care homes.

A Department of Health and Social Care spokeswoman said: “Throughout our coronavirus response we have been doing everything we can to ensure all staff and residents in care homes are protected.

“We are testing all residents and staff, have provided 200 million items of PPE and ring-fenced £600 million to prevent infections in care homes, with a further £3.7 billion available to councils to address pressures caused by the pandemic, including in adult social care.

“There is a high demand for tests and our laboratories continue to turn test results around as quickly as possible and we plan to rapidly expand it in the coming weeks as well as bringing in new technology to process tests faster.”

The concern over care homes comes as more than 3,000 coronavirus cases were recorded overall in the UK for the second day in a row – the first time since mid-May that recorded cases have been above that level on consecutive days.

The government said that as of 9am on Saturday, there had been a further 3,497 lab-confirmed cases in the UK, slightly lower than the 3,539 cases recorded on Friday.

Tough new Covid-19 lockdown measures were announced for parts of the UK on Friday as cases continued to rise and as the R number – the reproduction number of coronavirus transmission – climbed above one.

According to government advisers, the last time R was above one was in early March.

The public has been warned against having a “party weekend” ahead of rule changes on Monday, when social gatherings in England will be limited to groups of six people both indoors and outdoors, a new restriction dubbed the “rule of six”.

Police have been dispersing gatherings and handing out fixed penalty notices over the weekend, with one teenager facing a £10,000 fine for hosting a house party with dozens of guests in Nottingham.

Meanwhile, the Sunday Telegraph reported that up to 4.5 million people deemed to be at risk of serious illness from Covid-19 will be asked to stay at home again or given tailored advice on protecting themselves if cases rise to dangerous levels.

The newspaper said people identified using a new “risk model” based on factors such as underlying health conditions, age, sex and weight will receive letters containing specific advice.

The plan is initially due to operate in areas with severe levels of infection, but officials are prepared to roll it out nationwide if required, a source told the newspaper.

A DHSC spokeswoman said: “We keep all aspects of our response to the pandemic under review and in line with the advice of our scientific and medical experts.

“Shielding for the clinically extremely vulnerable has been paused since the start of August in most of the country while average rates of coronavirus remain low.

“Shielding is still advised in specific areas of the country where prevalence of the virus is higher.”

According to the paper, Prime Minister Boris Johnson is believed to be considering introducing a 10pm or 11pm curfew on restaurants, bars
and pubs if local measures are unable to bring the spread of the virus under control.

The move stems from a concern that adherence to social distancing measures diminishes the more people consume alcohol.