Why did Covid prove so lethal in care homes? Between 2 March and 12 June, there were 66,112 deaths of care home residents in England. Of these, 19,394 ‘involved’ Covid (in the Office of National Statistics’s own terminology) – 29.3 per cent of the total. As has been apparent from the beginning of this crisis, the risk of dying of Covid-19 sharply rises with age, so in that sense it is not surprising for deaths among care home residents to be high – but why has it proved so difficult to protect residents from the disease, not just in Britain but in many countries?

In Britain, there has been a focus on poor personal protective equipment and the practice of discharging elderly patients from NHS hospitals into care homes, without even testing them for Covid-19, thereby helping to send the virus into places where it was likely to cause the most damage. But a Swedish study shows another reason why it was so hard to keep Covid-19 out of care homes: large numbers of staff were unaware that they were infected. A study by Uppsala University reveals that 23 per cent of staff in 22 care homes tested positive for antibodies to SARS-CoV-2, showing that they had been infected at some point – but of that 23 per cent, 46.5 per cent had presented without symptoms. Put these two figures together and around one in ten care home staff may have been silent spreaders of the disease.

The problem with care home residents is that they need, well, care. It simply isn’t possible to isolate them. Staff need to handle those they are looking after and be in close contact with them for much of the day. Care homes can keep residents physically apart to an extent and ban visitors – but they can’t ban staff. On reflection, the only way you could ever really keep Covid-19 out of care homes is if staff were tested almost daily – and potentially dressed in full protective gear, as if they were intensive care nurses.

Covid-19 is far from the most lethal infectious disease in the world. Its most dangerous characteristic is that the virus is able to spread via so many asymptomatic individuals. That, combined with its tendency to strike the elderly, caused a fatal cocktail in care homes.