President Xi Jinping proposed creating a single international mechanism of health codes based on data from coronavirus tests when he addressed the G20's virtual summit, where many world leaders vowed to ensure a fair distribution of vaccines and drugs and do what is needed to support poorer countries.
The leaders, in a draft G20 communique, said on vaccines: "We will spare no effort to ensure their affordable and equitable access for all people."
And China is willing to "strengthen cooperation with other countries in the research and development, production and distribution of vaccines," Xi had said at the start of the two-day summit being hosted by Saudi Arabia.
There are five homegrown Chinese candidates for a vaccine now in the last phase of trials.
Xi went on to say the mechanism he had in mind would be based on nucleic acid tests following recognized QR codes.
Health codes have in fact been in effect in China since spring.
Each city has its own social media system with codes containing data about where a person has been and how safe areas are in terms of the epidemiological situation, indicated in green, orange or red.
Chinese nationals can get into any building, transport or attend an event if the code is green.
The pandemic, which has thrown the world into a deep recession, and efforts to underpin a rebound in 2021 were at the top of the G20 agenda.
Leaders are concerned the pandemic might deepen divisions between rich and poor. "We need to avoid at all costs a scenario of a two-speed world where only the richer can protect themselves against the virus and restart normal lives," France's President Emmanuel Macron said.
To do that, the European Union urged G20 leaders to put more money into a global project for vaccines, tests and therapeutics and distributing vaccines.
European Commission head Ursula von der Leyen called for US$4.5 billion (HK$35.1 billion) to be put into that effort, saying: "We need to show global solidarity."
The EU proposed a treaty on pandemics.
"A treaty would help us respond more quickly and in a more coordinated manner," European Council president Charles Michel said.
Germany was contributing more than 500 million euros (HK$4.6 billion) to the effort, Chancellor Angela Merkel said.
While the global economy is recovering from the depths of the crisis, momentum is slowing in countries with resurgent infection rates, the International Monetary Fund warned.
Especially vulnerable are the poor and highly indebted countries, which are "on the precipice of financial ruin and escalating poverty, hunger and untold suffering," United Nations secretary-general Antonio Guterres had said.
Russia's President Vladimir Putin offered to provide Russia's Sputnik V coronavirus vaccine to other countries and said Moscow was preparing two more vaccines.
And Donald Trump, who has just lost the US presidency - but refused to concede defeat - addressed leaders briefly on the need to restore economic growth. Then he went golfing.