On the eve of the 40th anniversary of launching of the Expanded Programme on Immunization (EPI) in 1974, during the twenty-seventh World Health Assembly (WHA), fundamental questions about the level of financing needed to sustain achievements and scale up the EPI in low- and lower-middle income countries continue to permeate the discourse on the economics of immunization. The answer to this question is all the more important in light of the fact that at the sixty-fifth WHA in 2012, ministers of health embraced the Global Vaccine Action Plan (GVAP) – a 10-year global strategic plan for immunization. But how much – and in what areas – are the investments needed for this decade? Today, improved transparency in pricing information allows for relatively accurate vaccine cost estimates.2 Unfortunately, trends in the health system costs of delivering vaccination beyond the cost of the vaccines themselves continue to be poorly understood. During the EPI’s first three decades of existence, they were fairly homogenous. The six basic antigens included in the EPI were inexpensive and health system inputs, such as the human resources for vaccination and the vaccine supply chain and logistics infrastructure, accounted for the largest share of total costs in country programmes. It was common knowledge that EPI vaccines represented 20% of overall investment in national immunization programmes in low- and lower-middle income countries.