As countries consider how they will invest in essential improvements to their defenses against future health threats, we propose a three-layer investment framework approach for the most effective use of their resources. The three layers include: Layer 1: Risk Reduction - Promoting prevention and community preparedness; Layer 2: Detection, containment, and mitigation capabilities; Layer 3: Advanced case management and surge response. This framework prioritizes interventions that prevent a public health threat from developing in the first place (Layer 1), and limiting its spread should one emerge (Layer 2), and not just managing a widespread crisis that compromises health systems' ability to sustainably deliver care (Layer 3). All three layers play a role in achieving health system resilience, however, not all of them have been equally leveraged in the past, as per the analysis conducted. We offer a glimpse of the relatively low cost of investments in improving the operation of the weakest parts of the three layers. The Layer 1 functions (public health; prevention, and community preparedness) are estimated to be between $2 to $4 per capita in low-income countries (LICs) and low and low- and middle-income countries (LMICs) respectively. The framework applies equally to short-term communicable disease epidemics, as well as slow-moving non-communicable disease trends. Health threats vary in the pace of the needed response, but all require a system that is resilient across multiple layers of response.

In the form of country cases, we share lessons learned across different continents. Though there is no universal blueprint for every setting, it behooves all countries to seize the moment and invest in the three layers in ways that fit their needs. As the efforts for building emergency-ready health systems intensifies across the globe, the book provides a practical investment framework and a diverse set of country cases to inform decision-making and strategic resource allocations.