Current State of Hazard Vulnerability Analysis (HVA) Frameworks

In the United States, the Assistant Secretary for Preparedness and Response (ASPR), through the Department of Health and Human Services (HHS), provides hospitals and regional managers with an array of HVA frameworks, resources, and examples through its Technical Resources, Assistance Center, and Information Exchange (TRACIE) website. ^{Reference Alberts, Aronson and Barbiere16} ASPR TRACIE offers many HVA templates ¹⁷ that provide methodological approaches to classifying hazards and hazard impacts, as well as a way for organizations (or localities) to gauge preparedness and vulnerability to individual disasters. Some of the most commonly used HVA tools are the Kaiser Permanente framework, ¹⁸ the Pennsylvania Public Health Risk Assessment Tool (PHRAT), ¹⁹ and the Threat/Hazard Assessment Module (THAM). ²⁰ These frameworks, especially the Kaiser Permanente HVA, are now widely used across the United States and internationally for regional and hospital disaster preparedness. ^{Reference Fares, Femino and Sayah21–Reference Niu, Zhang and Jiao24}

The Kaiser Permanente tool is primarily targeted at hospitals and health care organizations and provides a method to determine organizational planning priorities and establish the risk of individual hazards. ¹⁸ The template classifies hazard impact along human, property, and business dimensions, though it does not allow for additional stratification of at-risk populations or impacts within each dimension. Like the Kaiser Permanente tool, the PHRAT framework ¹⁹ helps assess hazard risk and establish planning priorities, yet it is distinct through its further distillation of hazard impact categories and incorporation of an in-depth population impact analysis alongside specific threats. The PHRAT allows an emergency manager to integrate the size of at-risk populations (eg, children age 18 and under, older adults age 65 and older, those with disabilities) as well as to care for these populations during disasters if specific procedures are in place. Finally, the Threat/Hazard Assessment Module (THAM) modality within the HHS risk identification and site criticality (RISC) toolkit ²⁰ contains built-in data to help organizations identify hazard risk based upon geographic location and other inputs. THAM does not allow users to input specific population impacts per hazard.

Regional and hospital-based emergency managers across the world use the Kaiser Permanente, PHRAT, and THAM HVA models, along with several other templates and resources offered through ASPR TRACIE, to inform their own HVAs, with little to no modification of the original templates. However, the fact that the Kaiser Permanente and THAM models do not allow for any specific population inclusions (and even the PHRAT framework does not allow for detailed pediatric inputs) causes these templates to omit many of the pediatric considerations necessary to care for children during disasters. Even if an emergency manager wanted to modify an existing HVA template to include essential pediatric factors, the resources detailing those factors are not readily available. Instead, the majority of commonly disseminated resources available focus on helping caregivers, children, and families prepare and cope with disasters and do not provide a comprehensive framework targeted at regional or hospital emergency managers. ^25–29 As a result, without a pediatric-specific hazard vulnerability and preparedness model, regional and hospital-based emergency managers across the country struggle to incorporate pediatric risks and disaster impacts into their work. ^{14,Reference Lyle, Milton and Fagbuyi30,Reference Ferrer, Ramirez and Sauser31}

Creating a Pediatric-Specific HVA Template

In order to provide regional and hospital emergency managers with a flexible way to include children in their disaster preparedness efforts, we developed a novel pediatric HVA template to be used on its own or alongside existing frameworks. We based aspects of the template’s structure on a combination of HVA guides available from ASPR TRACIE ^{Reference Alberts, Aronson and Barbiere16} (eg, Kaiser Permanente, PHRAT, THAM), using our pooled expertise in pediatric disaster preparedness to produce a template that offered ease of use and best reflected the unique needs of children during crises. The sub-categories within the template, which detail a given hazard’s impact and apply specifically to children, were derived from frequently studied gaps in the pediatric disaster management literature. ^{Reference Dziuban, Peacock and Frogel1,14} Before finalizing the HVA template, we checked it for overall utility as well as compatibility with other major tools used for hospital and community vulnerability assessments.

The workbook-based template informs regional and hospital managers about their institution’s pediatric risk and resiliency as well as how prepared their regions and/or hospitals are for the pediatric consequences of those disasters (Supplemental Content, Pediatric HVA Template Workbook). It is not meant to be a thorough checklist of preparation (eg, the details, coordination, and policies of sheltering children during a displacement event) and instead spurs the inclusion of general pediatric considerations into HVAs. The template equips regional managers to think about children in disasters across multiple dimensions (eg, acute and long-term health impacts, shelter/food) and can be applied to all types of hazards. As listed hazards are intended to represent an impact to the entire region, as opposed to an individual hospital (eg, a tornado that affects a community, as opposed to damaging 1 hospital), it does not replace existing hospital-specific HVAs with intra-facility hazards (eg, water damage or power loss to a single hospital facility).

The pediatric HVA template allows managers to determine a hazard’s impact on children (impact score) and the probability of that hazard occurring, thereby establishing overall pediatric vulnerability to a given hazard (vulnerability score) (Figure 1). Managers can then input currently existing disaster preparedness efforts in order to ascertain their region’s and/or hospital’s risk to the hazard (overall risk score). The template’s construction provides managers with both the pediatric-specific impact across various categories (as in the PHRAT template) and the simplicity of a final risk score (as in the Kaiser Permanente template). Hazards included in the template were carefully chosen and based on those found in the Kaiser Permanente, PHRAT, and THAM templates.

Figure 1.

The pediatric HVA template. The pediatric HVA template allows emergency managers to determine a hazard’s impact on children, how vulnerable the region and/or hospital is to the hazard, and the risk of each hazard based on existing preparedness efforts. For each hazard, the template produces 3 unique scores that allow for different insights. The Hazard Impact Score is a weighted score of a hazard’s impact without incorporating the likelihood of occurrence or preparedness efforts. The Vulnerability Score combines a hazard’s impact with its likelihood of occurrence. Finally, the Risk Score is a weighted score that incorporates existing preparedness efforts into a hazard’s projected impact and likelihood of occurrence.

Hazard Impact and Severity Measures and Scores

To characterize a disaster’s effect on children, the HVA template breaks a given hazard into novel impact and severity measures, one of the first instances of an HVA employing pediatric-specific categories to determine a hazard’s impact (Figure 2). These measures mirror several of the PHRAT’s classifications and are broken into “human impact,” “health care system impact,” and “community safety infrastructure.” Each of these sections is then further distilled into sub-categories that uniquely apply to children. For example, the “community safety infrastructure” category within the pediatric template is further subdivided into sections that prompt managers to consider how displaced children will be brought back to their families (“family reunification” sub-category), how school and day care closures will affect children’s safety and a hospital’s workforce (“school/childcare” sub-category), as well as how a disaster threatens the shelter and food needs of children in the community (“shelter/food” sub-category).

Figure 2.

Impact/severity measure within the pediatric HVA template. The impact/severity measure allows emergency managers to determine how a given hazard will affect children as well as the magnitude of the impact. It is broken down into “human impact,” “health care system impact,” and “community safety infrastructure preparedness” categories.

The template asks managers to assign each category an impact score of 1 (low impact) to 3 (high impact). To assist with these score determinations, the template includes an impact scoring key that assigns each category descriptions and examples across low, medium, and high impacts (Figure 3). Descriptions and examples were derived from commonly outlined pediatric needs during disasters (eg, need for pediatric-specific decontamination units during chemical and biological exposures), ^{Reference Dziuban, Peacock and Frogel1,Reference Gilchrist and Simpson2,Reference Shirm, Liggin, Dick and Graham4,Reference Chung, Baum and Nyquist5,Reference Blake and Fry-Bowers12} existing characterizations of hazard impacts, ^{10,Reference Alberts, Aronson and Barbiere16} as well as descriptions within the PHRAT tool. ¹⁹

Figure 3.

Impact scoring key. The impact scoring key provides many different considerations for each impact/severity sub-category. These considerations align across impact levels, thereby allowing managers to easily assign a score. For example, within the “acute pediatric morbidity” sub-category, the physiologic impact across age distributions is classified as mild across all ages (low impact), mild to moderate across all ages and/or severe across 1-2 age distributions (medium impact), or significant across all ages and/or lethal across 1-2 age distributions (high impact).

Although the scoring key is comprehensive, managers have wide latitude in assigning scores as each sub-category contains multiple components. For example, the “hospital” sub-category under “health care systems impact” asks managers to examine the number of hospitals a hazard affects, hospital capacity, patient flow, and the pediatric-specific equipment a given hazard necessitates. A hazard may affect these components differently, thereby allowing a manager to decide which aspects are most influential in the sub-category’s final impact score. For example, within the “hospital” category, a biologic attack on 1 community might be “low impact” in that it affects a small number of hospitals yet “high impact” in that it necessitates more pediatric-specific equipment than the region is able to provide. The manager would need to weigh these contrasting impacts within the same category in order to assign a final numerical score.

Some of the categories within the impact scoring key encourage managers to review their regional pediatric demographics and surge capabilities before assigning a score (Supplemental Content, Figure 1). While this is not a requirement to completing the HVA, it provides a means for emergency managers to identify broad areas of potential vulnerability, such as if their region lacks pediatric intensive care beds or contains a pediatric population with an uneven distribution (eg, large percentage of 0–2-year-olds). Dividing the pediatric population into separate age ranges prompts managers to appreciate how specific hazards affect pediatric physiology differently, depending on age. It also provides a more holistic assessment of a region’s pediatric capabilities, as older children can likely be cared for in adult hospitals during a surge event.

To help illustrate how an emergency manager might use the impact scoring key, the HVA template itself includes 2 examples of hazards separated into impact/severity sub-categories (Supplemental Content, Figure 2). Each sub-category is assigned a score based on the components within the impact scoring key, with a rationale for why that score was chosen.

Hazard Probability Measures and Scores

For a region or hospital to understand its actual vulnerability to a given hazard, it needs to know both the impact the hazard will have on children as well as the likelihood of the hazard realistically occurring. Building off of decades of risk management theory (where in the simplest form, risk = impact x probability) ^{Reference Mamuji and Etkin32} and mirroring several other HVA templates, managers can assign a likelihood score to each hazard from 0 (implausible; no documented historical hazard) to 3 (high likelihood of occurring; hazard occurs every 5 years or more frequently). A weighted calculation then incorporates a hazard’s impact and likelihood of occurrence to produce a vulnerability score (ie, how susceptible a region and/or hospital is to a given hazard, without taking into account preparedness efforts).

Hazard Preparedness Measures and Scores

The final step in our pediatric HVA template incorporates hazard impact, hazard likelihood, and existing preparedness efforts in order to produce an overall hazard risk score. Hazard preparedness mirrors the broad hazard impact/severity categories and is separated into “human impact,” “health care system impact,” and “community safety infrastructure.” For a given hazard, emergency managers assign a preparedness score of 1 (low preparedness) to 3 (high preparedness) in each category. To assist with these score designations, the template includes a preparedness scoring key (Figure 4) that provides descriptions and examples for each category and numerical score. Similar to the impact scoring key, the preparedness scoring key is meant to serve as a guide and emergency managers are ultimately able to assign individual scores based on their own determinations.

Figure 4.

Preparedness scoring key. The preparedness scoring key provides examples and descriptions of low, medium, and high levels of preparedness. The preparedness categories (“human impact preparedness,” “health care system preparedness,” and “community safety infrastructure preparedness”) align with the hazard impact/severity categories.

In using the preparedness scores to produce a final hazard risk score, the HVA template considers both the numerical degree of hazard impact and the score in the corresponding preparedness category. Preparedness in any 1 category (eg, “human impact preparedness”) only mitigates the impact in the corresponding hazard impact category (eg, “human impact”). For example, if a hazard is predicted to have a significant health care systems impact (by affecting hospitals, public health, and emergency medical services), and the emergency manager indicates that the region has low health care system preparedness yet high human impact preparedness, the overall risk for that hazard will be much worse than if the region had high health care system preparedness yet low human impact preparedness.

Hazard Impact and Likelihood Weights

Understanding that different regions and institutions across the world face different types and degrees of threats, the pediatric HVA template was meant to be customizable. As a result, though the framework defaults to scoring weights that reflect expert opinion and weighting systems found in other templates, ^{Reference Alberts, Aronson and Barbiere16} emergency managers are able to assign weights to each hazard impact sub-category (eg, “family reunification”) based on which impacts they consider most consequential or relevant. Higher weighted categories have a more significant effect on final score determinations than lower weighted categories. Preparedness scores can also be weighted, so that higher preparedness has an even greater mitigating effect on the final risk score. These weighting features would be useful for emergency managers who want to customize the pediatric HVA based on prior experiences or unique characteristics of their region. For example, in a geographic region where past hurricanes have significantly impacted pediatric morbidity and mortality despite robust preparedness efforts, an emergency manager may choose to increase the acute pediatric morbidity impact weight and decrease the preparedness scoring weights, thereby more accurately reflecting hurricanes’ severe risk to the region.