Public health programmes have done enormous good in Africa and elsewhere in the global south, but have also been met with skepticism. This skepticism often takes the form of rumours about the motives or the results of the public health intervention. One recurrent theme in such rumours is the centrality of reproductive bodies (both male and female), and the perception that these bodies are being rendered sterile by toxic compounds given under the guise of improving health. Public health operations research has identified these rumours as significant obstacles to programme delivery, but they have been treated primarily as failures in communication, to be rectified by the provision of more accurate information. Using reports of such rumours from public health interventions in Africa, with emphasis on vaccines, I argue that these rumours are more than simply stories which are not true. The widespread rumour of sterility is a way of articulating broadly shared understandings about reproductive bodies, collective survival, and global asymmetries of power. I use Foucault's notion of biopolitics to theorize international public health programmes, and introduce the concept of counter-epistemic convergence to account for the ubiquity and persistence of sterility rumours.