Epidemiology provides a novel approach to understanding cybersecurity risk. It provides a systematic model for the analysis of likelihood, consequence, management and prevention measures. While current research exists on the analysis of individual cybersecurity risk factors, there is a significant research gap on the collective interaction of these risk factors and their impact on the risk of cybersecurity compromise. Effective cybersecurity risk management requires the estimation of the probability of infection, based on a comprehensive range of historical and environmental factors, including system or network configurations and characteristics. The application of epidemiology highlights two fundamental approaches to increasing the efficiency and potency of cybersecurity; the requirement for comprehensive analysis of all cybersecurity risk factors, not just specific network vulnerabilities or uses, and the requirement for a centralised reporting, monitoring and data centre for cybersecurity incidents to inform this analysis, and facilitate a collective community response to mitigating cybersecurity risks. This paper discusses these applications of epidemiology to cybersecurity, to highlight the importance of research which combines these macro and micro-level approaches to provide a definitive evaluation of cybersecurity risk.