Despite advances during the twentieth century, immunization coverage is far from universal and faces significant obstacles in both developing and developed countries. Weak policy emphasis on vaccination may be the result of the narrow view of its benefits in scientific and policy-making communities, which focus mainly on the averted costs of medical treatment. An investigation of the broader impacts of immunization shows that the benefits of vaccine programs—in particular, their economic effects via improved health—have been underestimated, thereby causing the rate of return to be underestimated.

Among Africa’s problems, chronic poverty and poor health stand out. Traditional development thinking has maintained that health improvements are a consequence of income growth. But new evidence shows that investing in health, with the aid of the international community, could make a big difference in Africa’s economic prospects. Moreover, some feasible, low-cost interventions would likely have high returns. The pathways by which health can make a difference economically include those based on the heightened effectiveness of labor, increased savings, more effective educational investments, and demographic change.

Falling mortality rates spurred by medical, nutritional and lifestyle changes have spurred a ‘demographic transition’ in a majority of the world’s countries. As couples realize their children are more likely to survive, they need, and eventually have, fewer of them to attain their desired family size. In addition, desired fertility tends to decline as earnings opportunities improve since forgone income is such a large portion of the cost of childrearing. In the lag between mortality and fertility declines, a ‘boom’ generation is created, which is larger than both preceding and successor cohorts. As this boom generation reaches working age, the combination of a greater supply of workers and fewer dependents to support gives countries the opportunity to collect a ‘demographic dividend’. If an appropriate policy environment is in place for making the most of this opportunity, the economic benefits can be, and in many cases have been, great.