When the Ebola epidemic broke out in West Africa in 2014, in took several months to get large amounts money (around $100 million) to the countries that needed it, according to the World Bank. In that time, thousands of people died. In an effort to fight the next pandemic faster, the World Bank has turned to global financial markets, issuing $425 million in “pandemic bonds” and related derivatives to pay for emergency relief.

The money raised comprises the bulk of a $500 million Pandemic Emergency Financial Facility that will provide funds for poor countries in case of outbreaks of infectious diseases over the next five years. The bonds are designed to transfer the risk of a health crisis in low-income countries to the global financial markets. World Bank president Jim Yong Kim said this will help move away from “the cycle of panic and neglect” that has characterized recent pandemics.

The pandemic bonds work like this: Investors buy the bonds and receive regular coupons payments in return. If there is an outbreak of disease, the investors don’t get their initial money back. There are two varieties of debt, both scheduled to mature in July 2020. The first bond raised $225 million and features an interest rate of around 7%. Payout on the bond is suspended if there is an outbreak of new influenza viruses or coronaviridae (SARS, MERS). The second, riskier bond raised $95 million at an interest rate of more than 11%. This bond keeps investors’ money if there is an outbreak of Filovirus, Coronavirus, Lassa Fever, Rift Valley Fever, and/or Crimean Congo Hemorrhagic Fever. The World Bank also issued $105 million in swap derivatives that work in a similar way.

These bonds are similar to catastrophe bonds, a $90 billion market used by insurance companies to shift risks of hurricanes, earthquakes, and other natural disasters onto the financial markets. The World Bank’s bond sale was 200% oversubscribed, with investors eager to get their hands on the high-yield returns on offer. The majority of buyers were from Europe and included dedicated catastrophe-bond investors, pension funds, and asset managers.

Despite recent innovations, such as a genetic tool that maps how viruses spread in real-time, the world remains unprepared to deal with an epidemic on a global scale. The World Bank estimates that the annual cost of “moderately severe to severe” pandemics is roughly $570 billion, or 0.7% of global GDP. If—or when—there is another severe outbreak, these new bonds are meant to cut the cost, in terms of both human lives and financial resources, of fighting infectious diseases. Ebola killed more than 11,000 people and reduced GDP in Guinea, Liberia, and Sierra Leone by $2.8 billion.