A licensed Ebola vaccine is closer than ever to becoming a reality.

Gavi, the Vaccine Allliance, has just signed a US $5 million advance purchase agreement for an Ebola vaccine that is in late-stage clinical testing.

The deal, made with drug company Merck, will ensure that the vaccine is submitted for a license by the end of 2017. Credit goes to Merck for taking over development of the experimental vaccine in 2014 and speeding up the initial phases of testing.

If the vaccine is approved by the Federal Drug Administration (FDA), Gavi will be able to begin buying and stockpiling it for use during potential future outbreaks.

In the meantime, Merck will keep 300,000 doses of the vaccine available for emergencies or for use in further clinical trials.

This announcement is a much needed morale booster for the health industry, which has been battling the persistence of Ebola since 2014. Just last week, Sierra Leone discovered a new case of the virus a day after the World Health Organization declared the outbreak in West Africa to be over.

It could also be a game changer in a world where pharmaceutical companies tend to prioritize vaccines that are guaranteed to turn a profit. Gavi’s decision to purchase the vaccine will hopefully encourage large pharmaceutical companies to begin developing vaccines against “outbreak diseases” (e.g., Sars), even if there is less of a business case to do so.

New cases of Ebola are likely far from over. But this vaccine, whose initial results are impressive, could be the answer to containing future flare ups. And (crossing fingers) it could be the drug that will prevent future epidemics.