Will there be a warning for the next pandemic?

How to best allocate resources to combat the threat of pathogen emergence remains an important open question. Using archetypes that characterize the link from genotype to fitness in both zoonotic reservoirs and humans, we show that, across a range of plausible conditions, emergences of pathogens with pandemic potential in humans are unlikely to be preceded by detectable, failed, attempts. Yet, the number of “failed” emergence events contains information about the emergence potential of zoonotic pathogens, and should modify our beliefs about the underlying fitness landscape. Our work suggests that the most important, modifiable, risk factors for emergence may be phenomena that alter fitness landscapes, such as viral ecology in bridge species and human immunological landscapes.