The team hammers out four key messages. First, the economic argument that is most likely to be repeated in the corridors of power: the returns from investment in healthcare are big. By avoiding long periods of poor health, we increase the value of additional life years (VALYs, in healthcare acronym jargon), which generates an economic return that outweighs the healthcare investment we've put in by a factor of between nine and 20. It's striking that spending what seems like a huge sum of money will often deliver big economic returns.

The second point is that the convergence is achievable in less than a generation. Presumably this means that investors can look to make money relatively quickly, too. Governments can be confident of balancing their books fairly soon after a large initial outlay. To be able to see an effect in a matter of years helps turn the convergence from a vision document to actionable policy.

The third point is that governments are underusing fiscal policies in healthcare. In other words, by increasing the tax on tobacco and alcohol, deaths from noncommunicable diseases and from injuries can be sharply reduced in low- and middle-income countries. For example, a 50% price increase in cigarettes in China would prevent 20 million deaths and produce tax revenue of $20bn annually in the next 50 years. The same price increase over the same time period in India would save 4 million lives and bring in an extra $2bn a year in tax. Reducing the subsidies paid to fossil fuel companies also has the effect of improving general health, mostly through the reduction in respiratory diseases.

But it's the fourth point that is most important for us: that universal healthcare is the most efficient way to achieve a convergence in global health. The Lancet's framework was written before Covid-19, but the response of various countries to the crisis shows that universal healthcare is a good protector for pandemics, too.

Jeremy Farrar is director of the Wellcome Trust, one of the world's largest medical research charities, with an endowment of about ￡30bn. As someone with experience of problem-solving in global health, he is well placed to advise us on how to spend the trillion dollars. "The bedrock of your spending must be on universal healthcare," he told me. An equitable system of healthcare is necessary to improve maternal health, child health, to improve end of life care and to fight epidemics. "Almost anything else is not equitable, not efficient and will not deliver what you need sustainably."