To better understand the economic value of vaccines, the Decade of Vaccine Economics (DoVE) project calculated the Return on Investment (ROI) of vaccine programs in 73 low- and middle-income countries. DoVE also estimated the Cost of Illness (COI) for three vaccine-preventable diseases in Bangladesh and Uganda. Finally, in Bangladesh, DoVE measured people’s Willingness to Pay (WTP) to reduce their risk of vaccine-preventable disease.