PART 4.1

PART 4.1

Mass vaccination was the tried-and-true approach to smallpox eradication. Mass vaccination success was measured by the percentage of the population that was vaccinated, in order to achieve herd immunity. Most countries, WHO and other multilateral organizations were committed to this approach and operationally tied the goals to this strategic approach. But it wasn’t working in poor countries in Africa and Asia. In India, health officials thought that if they could vaccinate 80% of the population, they would reach “herd immunity” and smallpox would not be able to spread. But there were many places where they could not reach 80% of the population. Some places were too densely populated and had too much disease for eradication to work when no more than 80% of the population was vaccinated. In other places, vaccination workers were rewarded for vaccinating lots of people and thus had an incentive for reporting higher than actual numbers of vaccinated people. Despite these problems with the mass vaccination approach, WHO was concerned that changing strategies would cause governments to lose confidence in the eradication program. They were quite certain that the mass vaccination strategy would work.

FEATURING

Dr. Bill Foege, Senior Advisor, Bill & Melinda Gates Foundation

Dr. Susmita Parashar, Associate Professor, Emory University School of Medicine