Since 2000, the United States government has been a strong partner of Gavi, the Vaccine Alliance, providing more than US$730 million through the end of December, 2015, to support the introduction of new and underutilized vaccines in the world’s poorest countries. Lower income countries receiving Gavi assistance have long been required to co-finance a portion of each vaccine dose procured with Gavi funds, with the expectation that as the countries reach lower middle-income country status (LMIC), they will eventually transition away from Gavi support. To date, at least 24 of the original 73 Gavi-eligible countries have started to transition, with 16 expected to complete the process by the end of 2018. The long history of U.S. support for global maternal and child health programs, its emphasis on assisting countries in strengthening their immunization programs, and considerable U.S. investments in Gavi over the past fifteen years all underscore why the U.S. has an interest in ensuring LMIC transitions from Gavi support proceed smoothly and sustainably.