Despite the demonstration of effectiveness and public health impact of Hib conjugate vaccines, the majority of infants from poorest countries do not yet have access to this safe and effective preventive intervention. This paper provides a descriptive analysis of the main characteristics of countries that have included Hib vaccine in their national immunization programmes before 2006. It highlights the importance of regularly analyzing the process of decision-making involved in implementation of public health interventions, in order to learn from cumulative experience and expedite the introduction of future interventions.