As a result, there are concerns that low-paid staff in multiple jobs and agency workers may unwittingly be spreading the virus between homes and in the wider community, making it harder to lift the lockdown.
Earlier this week, Boris Johnson said he “bitterly regrets” the crisis in care homes, which now account for around one in three coronavirus deaths, fuelling the highest death toll in Europe.
Sampling by the Office for National Statistics suggests that just 0.2 per cent of the population – around 200,000 people – may currently have coronavirus, but the Government’s advisers fear the rates among health and care workers may be five to 10 times as as high.
Earlier this week Sir Patrick Vallance, the Government’s chief scientific adviser, suggested that up to one in six of the population may have had the virus at some stage, with the highest figures in London.
Recent weeks have seen heated debate about whether those who have recovered from the virus are now protected against it.
But advisers are now understood to be increasingly confident that 95 per cent of coronavirus sufferers develop antibodies.
It remains unknown what degree of protection this offers, or how long it lasts, with patterns from other coronaviruses suggesting a timescale of two to three years is most likely.