The health crisis will be over sooner or later. What is needed now is exactly what you say, cooperation. Specifically China-Japan-US-EU cooperation, caused by the - possibly overblown - anti-virus measures. No single county can handle this economic mess on its own, it absolutely requires the hand-in-glove-coop of all the leading economies. If any of them still follows 'my country first', then the mess can't be tackled an we'll spiral down into an economic abyss.