How can a microbial approach to global health security protect life? Contemporary infection control mechanisms set the human and the pathogenic microbe against each other, as the victim versus the menace. This biomedical polarization persistently runs through the contemporary dominant mode of thinking about public health and infectious disease governance. Taking its cue from the currently accepted germ theory of disease, such mechanisms render a global city like Hong Kong not only pervasively "on alert" and under threat of unpredictable and pathogenic viruses and other microbes, it also gives rise to a hygiene and antimicrobial politics that is never entirely able to control pathogenic circulation. The article draws on recent advances in medical microbiology, which depart from germ theory, to invoke an ecological understanding of the human-microbe relation. Here, while a small number of viruses are pathogenic, the majority are benign; some are even essential to human life. Disease is not just the outcome of a pathogenic microbe infecting a human host but emerges from socioeconomic relations, which exacerbate human-animal-microbial interactions. In a final step, the article draws on Daoist thought to reflect on the ways that such a microbial understanding translates into life and city dwelling., (© The Author(s) (2019). Published by Oxford University Press on behalf of the International Studies Association.)