Temporary care workers transmitted Covid-19 between care homes as cases surged, according to an unpublished government study which used genome tracking to investigate outbreaks. In evidence that raises further questions about ministers’ claims to have “thrown a protective ring around care homes”, it emerged that agency workers – often employed on zero-hours contracts – unwittingly spread the infection as the pandemic grew, according to the study by Public Health England (PHE). The genome tracking research into the behaviour of the virus in six care homes in London found that, in some cases, workers who transmitted coronavirus had been drafted in to cover for care home staff who were self-isolating expressly to prevent the vulnerable people they look after from becoming infected. At least 22,000 people are estimated to have died in care homes in England and Wales directly or indirectly from Covid-19. While the peak appears to have passed, the crisis is far from over for the country’s 400,000 care home residents, with some providers reporting fresh outbreaks and hospitalisations at the weekend. During flu pandemic planning in 2018, a report from social care directors warned ministers that frontline care workers would need advice on “controlling cross-infection”. A 2019 PHE document about flu pandemic preparations called “Infection prevention and control: an outbreak information pack for care homes” urged operators to “try to avoid moving staff between homes and floors”. But the DHSC’s social care plan, published on 16 April, mentions nothing about restricting staff movements between homes in its chapter on “controlling the spread of infection in care homes”. Results from the PHE study, conducted over Easter weekend from 11 to 13 April, have been known about inside the Department of Health and Social Care (DHSC) since at least the end of last month, but were only circulated last week to care home providers, councils and local directors of public health. It was referenced as part of a £600m infection control plan, which adult social care directors said came “tragically late in the day” given the peak of deaths in care homes appeared to have already passed. The study warned: “Infection is spreading from care home to care home, linked to changed patterns of staffing, working across and moving between homes.” The infection could be introduced by “bank staff” – floating workers used to fill temporary vacancies in different homes – it said, adding that workers were often asymptomatic so “by the time local health protection teams are informed of an outbreak substantial transmission may already have occurred”. The existence of the study was flagged to care operators and councils last week when the care minister, Helen Whately, announced details of a £600m “infection control fund” for care homes to allow providers to pay extra to carers who normally work in several homes in exchange for working in only one facility. The new plan to cut infection rates in care settings included instructions to councils and operators to “take all possible steps to minimise staff movement between care homes, to stop infection spreading between locations” and that “subject to maintaining safe staffing levels, providers should employ staff to work at a single location”. The £600m funding is “intended to help providers pay for additional staff and/or maintain the normal wages of staff who, in order to reduce the spread of infection, need to reduce the number of establishments in which they work”. Documents seen by the Guardian show that on 30 April, shortly after a sharp rise of 4,300 care home deaths in a fortnight in England and Wales, DHSC officials had drafted plans for “comprehensive infection prevention and control measures” in care homes. These included measures “minimising the extent to which care workers are moving between different units”. However, they were not published until last Thursday – a fortnight later. In the meantime, at least another 2,500 people died in English care homes, according to the Office for National Statistics. Last week, Boris Johnson admitted there had been “an appalling epidemic in care homes”. DHSC said it would not comment on leaked documents and said the study would be published shortly. It stressed that it started working on new guidance and funding as soon as it received early results from the report. “We are working around the clock to make sure care homes, and our frontline social care workforce, are getting the support they need to protect their residents and tackle coronavirus,” a spokesperson said. “Our help to care homes, which includes financial support, infection control training and supplies of PPE, has meant that two-thirds of England’s care homes have had no outbreak at all.” Labour attacked the slowness of the government response. “The prime minister was warned about the risks of care workers moving between homes spreading the virus at Prime Minister’s Questions on 25 March,” said Liz Kendall, the shadow care minister. “Yet it has taken ministers until now to fund care homes to reduce their reliance on bank and agency staff.” She said the pandemic had “brutally exposed how insecure, undervalued and underpaid care work is. “The prevalence of zero-hours contracts, high vacancy rates and high staff turnover have fuelled the reliance on agency and bank staff with all the problems that brings. We need a fundamental rethink of social care as we emerge from this pandemic, and an essential part of this must be to ensure that care workers get the pay, status and career progression this vital sector deserves.” The DHSC also examined three US studies of care home outbreaks showing high levels of transmission by asymptomatic carriers and staff members working in more than one facility. A report published in March about an outbreak in February at a home in Washington state where 23 people died found “staff members working in multiple facilities contributed to intra- and inter-facility spread”. Care operators have been increasingly reliant on flexible workers to fill shifts, with absence rates caused by self-isolation among permanent staff running as high as 25% at the peak of outbreaks. Until recent weeks, shortages of PPE exacerbated concerns that care staff risked spreading the illness and family members have complained of loved ones put at risk by care workers travelling to and from work without changing clothes. Vic Rayner, the executive director of the National Care Forum, which represents charitable care providers, said: “Staff have always been extremely concerned with the potential for spreading the virus. It would be the last thing any of them want to do. “They have been putting the wellbeing of the people they are caring for above themselves. Good care homes have been implementing restrictions on movement from day one and have been buying out agency staff at their own cost [so they only work in one home]. “The challenge here is they are looking for restrictions on movement when we are already running with a high level of vacancies in the sector, people self-isolating with symptoms and now the roll out of testing of asymptomatic staff which will increase the numbers self-isolating again.”