During the financial crisis of 2008, G20 leaders coordinated a global response. And in other emergencies — tsunamis, civil wars, or epidemics — coalitions of countries have convened donor conferences to generate the necessary resources. Today, we need both: a G20 task force to coordinate international support and a donors’ conference to make that support effective.

A decade ago, the answer to the immediate economic crisis was to address the under-capitalisation of the global banking system. This time, the economic crisis will not end until the health emergency is addressed, and the health emergency will not end by addressing the disease in one country alone. It can end only when all countries recover from COVID-19 and it is prevented from returning on a regular basis.

All health-care systems and societies are buckling under the strain of the coronavirus. But if it spreads in African, Asian, and Latin American cities — which have little testing equipment and fragile health systems, and where social-distancing will be impossible — it will cause devastation, will persist, and may fuel other outbreaks worldwide.

The way to end the crisis sooner is to do what we have not done for years: fund the public health, scientific, and economic agencies that stand between us and global disaster. World leaders should agree to an initial $8bn: that’s $1bn for the World Health Organisation to continue its vital work during 2020, and the remainder for the Coalition for Epidemic Preparedness Innovations to coordinate efforts to develop, manufacture, and distribute diagnostics, therapeutics, and vaccines (with equitable access for all countries).

There must also be funding to meet the global need for ventilators and personal protective equipment. Rather than having each country or province scramble for a share of existing capacity, with all the cost-inflationary competition that would bring, we should vastly increase capacity by coordinating the global production and procurement of such medical supplies. And, if a vaccine becomes available, funding must be allocated to deliver it to the poorest countries.

According to even the most optimistic estimates, there will be 900,000 deaths in Asia and 300,000 in Africa. Developing countries not only lack modern health systems; they also have inadequate social safety nets. At least $35bn is needed to provide medical supplies and recruit staff.

And yet, 30% of countries have no COVID-19 national preparedness and response plans, according to the WHO, and only half have a national infection prevention and control programme. Many lack adequate water, sanitation, and hygiene standards in their health-care facilities. And while richer countries will have only one-seventh of the hospital beds they need for critical care, poor countries will have far, far fewer.

National governments are also attempting to counter the slide in their economies. But, to prevent a liquidity crisis from turning into a solvency crisis, and today’s global recession from becoming tomorrow’s depression, better-coordinated fiscal, monetary, and trade measures are needed.

The fiscal-stimulus packages now being implemented in some countries will be much more effective if all countries join in. But if we are to limit mass redundancies (which are already occurring on a frightening scale), it is also vital that banks follow through rapidly on government loan guarantees and provide the cash support that companies and their workers need.

The poorest countries need economic assistance. The international community should waive this year’s developing-country debt repayments, including $44bn due from Africa. But at least $150bn in new funds will be needed to protect developing economies.

The World Bank can scale up country support, while still meeting its lending ceiling. But that will not be enough. In 2009, during the ‘Great Recession,’ World Bank spending went from $16bn to $46bn. A similar expansion of resources should be guaranteed now. The International Monetary Fund should allocate around $500-600bn in special drawing rights (SDRs).

Ideally, all this should be agreed this week and be confirmed by the IMF and the World Bank Development Committee when they meet on April 17-19. This may be the most viable exit strategy available to the world. If the price seems high, the consequences of not paying it could well be catastrophic.

• Gordon Brown, former prime minister of Britain, is United Nations special envoy for global education and chair of the International Commission on Financing Global Education Opportunity. Erik Berglöf, a former chief economist at the European Bank for Reconstruction and Development, is director of the Institute of Global Affairs at the London School of Economics and Political Science.

Jeremy Farrar is director of the Wellcome Trust, a global charitable foundation dedicated to improving health.