My limited understanding understanding is that it automatically releases funding (from the WHO and other bodies) to help with the crisis. It should also trigger some catastrophe and pandemic bond clauses, meaning investors who bought these bonds will lose their money as it now goes towards relief funding.
Pandemic bond clauses? Why does this sound like people gambling against the world not having a pandemic
That's basically what it is. Another way to think about it is it's a way for the World Bank / WHO to buy insurance against pandemics. Sell high yield bonds that default when a pandemic happens.