During the Covid-19 pandemic, we’ve seen a familiar pattern. A major disease quickly becomes something that, by and large, inconveniences the rich and kills the poor.

Those with lower incomes are more likely to catch coronavirus (because of factors such as crowded accommodation) and more likely to die (due to anything from obesity to poorer access to healthcare). This happens in almost every sphere of health. The rich tend to be healthier and live longer.

If you take life expectancy in the UK, there is a strong correlation between wealth and years lived. The rich south-east has most of the longest lived areas. Poorer Scotland has few. A man born in Glasgow is likely to live almost ten years less than one born in Hampshire. In the US, you see a similar pattern. People from prosperous states like Hawaii, California and New York live considerably longer than those in poor states, such as in the Deep South.

But this is only the beginning. Researchers at University College London recently analysed data from the English Longitudinal Study of Ageing and the US Health and Retirement Study. They found that rich people’s extra years of life were also likely to be spent in better health. Men from the wealthiest groups were likely to have 31 years of healthy life after 50; those from the poorest groups 22-23. Women from the wealthiest groups got an extra 33 healthy years compared to 24-25 years in the poorest groups.

Another ELSA-based paper published in June went further. This found “a more rapid deterioration” in physical, mental and social functions among poorer people. The findings were often quite surprising: between 2004 and 2012, walking speed fell 38 per cent more in the least well-off group than among the richest. UCL’s Professor Andrew Steptoe, who led the study, concluded that the evidence showed “the corrosive nature of lower socio-economic status on our bodies, our minds, and our capabilities.”

Wealth correlates with everything you need for a good life, ranging from good food to a lack of money worries. Even in the current pandemic, the professional classes enjoy many health-related advantages. Jobs that can easily be done from home, for example, and big houses in which to work.

Top earners do better in the UK than the US on criteria ranging from diabetes to mental health, even though rich Americans earn more than twice as much

OK, but what about the future? It is certain that technologies ranging from AI to 3D printing of artificial organs will benefit the rich first — possibly giving them extra decades of healthy life. However, many innovations such as telemedicine may bring important treatments to all. Dr Greg Bailey, chief executive of Juvenescence, a US-UK longevity start-up, recently told me that the market for anti-ageing treatments is vast and that a drug for half a billion people can be cheap.

But it is significant that, while there are strong links between wealth and health within countries, internationally, the connection is weaker. Life expectancy is almost the same in Cuba as in the US despite an eightfold difference in per capita GDP.

This points to other factors, and a big one is inequality within a country. Relative social deprivation — the gap between rich and poor — undermines health standards. Even the greatest medical advances may not close the health gap between America’s rich and poor.

It’s instructive to compare the UK and the US. Both have similar problems with health standards and income inequality. But the US is worse: a University of Michigan / UCL study unsurprisingly found that poor Americans suffered far worse health than their poor English counterparts. More intriguingly, top income earners did better in the UK than the US on criteria ranging from diabetes to mental health, even though rich Americans earn more than twice as much on average ($144,000 vs $71,000 a year).

So what’s going on? Well, for starters universal healthcare, as provided in Britain, seems to benefit everyone, even those with private healthcare. You have a problem, you just walk into a hospital. But the key point is that the problems caused by inequality — not only poor health but also low pay, unemployment and crime — permeate societies. If communities are polarised, the rich too are worried. In a dog-eat-dog world, you’re always looking over your shoulder at the dog just behind you.

In their books The Spirit Level and The Inner Level, Richard Wilkinson and Kate Pickett, two London-based epidemiologists, argue that inequality affects both rich and poor, physically and mentally. They point to the low levels of mental illness in relatively equal Japan and the far higher levels in the far more unequal US.

So if Americans, even rich Americans, want to live as long as Europeans or Japanese, they have two battles to fight. The first, hard enough, is to fix healthcare. The second, much tougher, is to tackle inequality. Meanwhile, the rich in countries where inequality appears to be increasing (including the UK) would do well to remember that it harms them too.

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