Pandemic preparedness and response interventions can be classified by their timing with respect to pandemic occurrence: the prepandemic period, the spark period, and the spread period, as shown in box 17.1.
Whereas some interventions clearly fall under the purview of a single authority, responsibility for implementing and scaling up many critical aspects of preparedness and response is spread across multiple authorities, which play complementary, interlocking, and, in some cases, overlapping roles (Brattberg and Rhinard 2011). The governance of pandemic preparedness and response is complex, with authority fragmented across international, national, and subnational institutions, as well as among multiple organizations with functional responsibility for specific tasks (Hooghe and Marks 2003). Pandemic preparedness requires close coordination across public and private sector actors: vaccine development requires close coordination between government and vaccine producers; whereas critical response measures—such as managing quarantines—requires engagement between nonprofit organizations (hospitals, clinics, and nongovernmental organizations), public health authorities, affected communities and civil society groups, and the security sector.
Historical pandemics offer only a partial view to guide preparedness and response activities. Many countries and organizations have used the historical influenza pandemics in 1918, 1957, and 1968 to estimate the potential morbidity and mortality burden during a future pandemic (WHO 2016c). However, using these moderate-to-severe events to plan for a mild pandemic (for example, the 2009 influenza pandemic) can lead to an overzealous response—such as widespread mandatory school closures—that may create unintended negative economic consequences (Kelly and others 2011). And although the 1918 influenza pandemic is sometimes considered a “worst-case scenario” for planning purposes, possible scenarios today could be far more damaging—such as if a highly transmissible, highly virulent influenza virus were to emerge. Especially in LMICs, intensive care unit (ICU) beds and therapies for acute respiratory distress syndrome are in short supply, which could lead to many casualties (Osterholm 2005).
Situational awareness—in the context of pandemic preparedness—can be defined as having an accurate, up-to-date view of potential or ongoing infectious disease threats (including through traditional surveillance in humans and animals) and the resources (human, financial, informational, and institutional) available to manage those threats (ASPR 2014). Situational awareness is a crucial activity at all stages of a pandemic, including prepandemic, spark, and spread periods. It requires the support of health care resources (such as hospitals, doctors, and nurses), diagnostic infrastructure, and communications systems. It also requires the population to have access to and trust in the health care system.
Situational awareness supports policy decisions by tracking if and where disease transmission is occurring, detecting the most effective methods to reduce transmissibility, and deciding where to allocate resources. During a pandemic, situational awareness allows for monitoring to understand the course a pandemic is taking and whether intervention measures are effective.
The ability to detect the presence of a pandemic requires the health care workforce to recognize the illness and to have the technical and laboratory capacity to identify the pathogen (or rule out known pathogens) and respond to surges of clinical specimens in a timely manner. Rapid identification reduces risk by enabling infected persons to be isolated and given appropriate clinical care. During the 2003 SARS pandemic, a one-week delay in applying control measures may have nearly tripled the size of the outbreak and increased its duration by four weeks (Wallinga and Teunis 2004).
Endemic infectious diseases can affect pandemic detection by complicating the differential diagnosis and rapid identification of pandemic cases. Overlapping symptoms between endemic and emerging pathogens—for instance, between dengue and Zika or between malaria and Ebola—have hampered the early identification of cases (de Wit and others 2016; Waggoner and Pinsky 2016). This difficulty suggests a role for investment in the development and deployment of rapid diagnostic tests in regions with a high burden of endemic pathogens and high risk of disease emergence or importation (Yamey and others 2017). Additional constraints affecting epidemic and pandemic situational awareness in LMICs are described in box 17.2.