Imagine that you are responsible for evaluating the potential impact of a $5M grant to scientific research into a vaccine for preventing new syphilis cases. You have the following pieces of information, which you can assume are 100% true for the purpose of this exercise, and you can assume you have all the numbers you need. What is the social ROI of the grant? Your answer should be in terms of a multiple of the cost of the grant (e.g. if the social return was $500M, the ROI would be 100x). You may or may not need all of the information provided. Total number of new syphilis cases per year: 6M Lost DALYS [disability adjusted life years] per new case of syphilis: 1 Rate at which syphilis cases are declining each year from other improvements in detection and treatment (with or without vaccine): 2%/year Time discount rate: 0% Years until new vaccine if this grant fails: 20 Years until new vaccine if this grant succeeds: 17 Number of labs funded by the grant: 3 Chance of grant succeeding: 5% Share of new syphilis cases prevented by vaccine once released (does not cumulate annually): 30% Value per DALY: $100,000 Share of new syphilis cases in low and middle income countries: 85%