In the UK, more than 500,000 people signed up to be National Health Service volunteers in 24 hours.
Amid this heartening outbreak of neighbourliness, however, an unsettling question is being asked.
This particular plague doesn't seem to threaten everyone equally. While the young are by no means immune, coronavirus disproportionately harms the old. So, some critics are murmuring, should we really be sabotaging the economy and the futures of the young to save grandma?
I didn't want to interpret this crisis that way. But a liberal-minded friend in London forced me to think about it. "If I was a 40-year-old woman who had been denied a life-saving cancer drug because it was judged too expensive," she said to me, "I wonder how I'd feel about throwing the whole NHS at a bunch of old people who were reaching their final years anyway. And damaging the futures of the young in the bargain."
My shocked response was that this is a pandemic, and the usual rules can't apply. The NHS sometimes uses a metric of "quality adjusted life years" when trying to make very difficult decisions. This considers the cost of each additional year of life that might be gained by a treatment and the potential quality of life gained.
But it would be unconscionable to convert that into a blanket refusal to treat people over a certain age. It would also be counter-productive. In this crisis, our healthcare system itself is under threat, for both young and old.
To preserve health systems and combat the virus, governments around the world have chosen to slow down their economies. That could of course have terrible repercussions on the younger generation, some of whom will graduate this summer into a world of no jobs.
It is why we must do everything possible to ensure that we get a recession not a depression.
A cruder version of the question has been put by Donald Trump, whose re-election strategy depends on a strong economy. Calling on Americans to be back at work by Easter, the US president suggested that more people might die from a "terrible economy" than from the virus.
Texas lieutenant-governor Dan Patrick has said that grandparents like him shouldn't "sacrifice the country".
I have two problems with this argument. The first is that pitting the elderly against the stock market is a false choice. Unless we halt the pandemic, there can be no functioning economy, because there will be no confidence.
The second is with the belief that falling gross domestic product will reduce life expectancy. That is the assumption made by Trump and by risk management professor Philip Thomas. His paper, which has not yet been peer-reviewed, claims that if lockdown measures crash the economy, this could end up costing more lives than the virus.
Using a technique developed to measure the cost-effectiveness of safety measures in nuclear power stations, he calculates that the way to save most UK lives would be through a 12-month lockdown, followed by widespread vaccination.
However he fears the number of lives saved that way could be more than offset by a later fall in life expectancy, if the lockdown resulted in a hit to GDP of more 6.4 per cent or more.
This is a sobering account. It is true that the Depression showed that prolonged deprivation can lead to suicide, poor nutrition, and domestic violence.
This is also supported by recent statistics that show life expectancy among some deprived groups has stalled in the UK, and gone backwards in America.
These issues needed more attention from governments, even before the virus struck — and they will demand more focus once it is conquered.
But at the moment, it seems more likely that we will get a deep, short recession, not a lengthy one. If companies can keep struggling on, and receive the promised wage support to keep on employing UK workers, we can hope that consumer spending and investment will rebound, without significant impact on life expectancy.
Prof Thomas has also looked at the issue of life years. If the virus were allowed to run its course without a lockdown, he calculates that almost 1 million Britons could die (far more than most epidemiologists estimate).
If most of the dead are elderly, he estimates this would equate to the deaths of 400,000 average age adults in terms of life years lost. That would match the death toll of the second world war.
No government would choose to sacrifice that many people — and the public would not support it. It is an interesting calculation, but it seems to me that it makes its own counterargument.
Right now, instead of being at war with each other, it feels as though the generations have never been closer. Far from whingeing about grandma, the country is mobilising to support her. Students have set up websites to help local elderly people get help. Children are sending letters to care homes. And the old are locking themselves away — not just to save themselves but to protect the NHS for all of us.
It seems to me we must do whatever it takes, and spend whatever it costs, to save lives. That does not mean that there is no trade-off. When this grim period comes to an end, and we defeat the virus, we will need to remember the young — and build a society that works better for them.
- The writer is a temporary adviser to the UK Department of Health and Social Care and the author of 'Extra Time'.