Analysis of forces driving change in global health governance is an emerging research agenda. Here we apply analytical tools derived from international relations theory. The study utlilized two explanatory perspectives, individual leadership and the interests of key non-state actors in explaining regime formation. The case study is the formation of the Global Alliance for Vaccines and Immunization 1995-1999. Findings show that individuals associated with scientific communities were able to make the World Bank and the Gates Foundation champions of a new coordinating mechanism for vaccine introduction. The authority of the WHO was also important in the process. The paper also discusses the potential contribution of the international relations approach compared to policy reserach.