Given the ever-looming reality of the next pandemic threat, my project provides a fundamental re-conceptualization of the implicit social theory that undergirds current global health responses. I build on 18 months of extensive field research in Austria, studying the changes wrought on care practices and illness experiences by new Hepatitis C antiviral drugs, whose curative potential fueled an expansive global health virus eradication project. I integrate diverse social-science concepts to analyze the material and discursive mechanisms that animate particular forms of applying biomedical and epidemiological knowledge in contemporary society and global health politics. I will leverage my findings to conceive of a different kind of social theory of infectivity that accepts not just the reality of large-scale and globe-spanning viral infections, but also responsibility for a connected global society. I argue that the way we address and live with infectivity is integral to the way we choose (or not) to live as a society. In turn, changing our ways will unleash the full systemic potential of the life and social sciences to meet infectious challenges present and future.