Introduction

The anticipated worldwide morbidity, mortality, and social disruption from an influenza pandemic [1] require detailed and tested approaches to staffing and resource allocation in public health systems [2]. The willingness of health responders to report to duty during an influenza pandemic is a highly salient concern given the “inevitable”nature of this threat [3] and its associated challenges. Scant margin exists in the nation's public health system for local health department workers – the backbone of public health system readiness – to “opt out” of response duties, given limitations of health system surge capacity [4], public health personnel shortages [5], and continued steep learning curves associated with relatively new 24/7 response expectations for health department employees.

The unwillingness of some health workers to place themselves at risk of exposure to emerging infectious diseases was observed during the 2003 SARS epidemic and the early years of the HIV/AIDS epidemic [6]. In the aftermath of the terror attacks of September 11, 2001 and the ensuing anthrax bioterrorism attacks, a growing body of research literature has examined willingness to respond to large-scale emergencies among a variety of health-related cohorts [7]–[14]. Despite the evidence for fundamental distinctions between ability and willingness to respond [7], [13], there remains a gap in the public health preparedness literature on training approaches that explicitly address response willingness (attitude) as a discrete outcome. Based on the principle that “all disasters begin locally”, these observations underscore a fundamental need to understand root causes of local public health workers' barriers to response willingness, as a basis for identifying and addressing public health response system gaps in this domain.

A variety of risk perception theories have been suggested and may help to identify barriers to health personnel adopting an emergency responder role. One prominent model conceptualizes risk perception as the sum of “hazard” and “outrage”, where hazard is a product of risk magnitude and probability, and outrage is a function of other peripheral influences independent of the actual risk, such as perceived authority, trust, and situational control [15].

Among the public health workforce, recent applications of this “Risk = Hazard+Outrage” model have uncovered a variety of potential peripheral risk perception influences on health department workers' response willingness apart from the actual hazard [16]. For example, in a 2005 pilot study conducted in three local health departments in Maryland, we found that a health department employee's individual perceived level of importance in their agency's response efforts was a particularly strong peripheral influence on response willingness toward an influenza pandemic [8].

The cumulative evidence from these studies suggests that willingness to respond is multidimensional. Specifically, its dimensions appear to include: 1) perceived threat, as evidenced by findings of scenario-specific response willingness rates; and 2) perceived efficacy, as highlighted by the powerful influences of response efficacy (“My response makes a difference”) and self-efficacy (“I can do what is expected of me as a responder”). Further, preparedness training for public health workers is a form of risk communication in itself, intended to build health department workers' efficacy in the face of a variety of hazards. To build a public health workforce that is not only able to respond, but also willing to do so, the above observations suggest the need for a unifying paradigm that can address both the threat and efficacy dimensions of willingness to respond. To date, the research literature on public health emergency response willingness has lacked such a paradigm.

The Extended Parallel Process Model (EPPM) [Figure 1] has been found to be useful for understanding adaptive behavior in the face of unknown risk [17]. First proposed by Witte in the early 1990s [18], the EPPM represents an integration and expansion of previous psychosocial models of “fear appeal.” The model focuses on messages that are received by both individuals and collectively by groups. Importantly, while the model was first developed to explain individual behavior [18], it has since been directly applied to the analysis of collective behavior [19].

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Figure 1. Extended Parallel Process Model.

Witte's Extended Parallel Process Model (EPPM) describes how people, when faced with a potential hazard, will sequentially appraise the threat and efficacy content of related health and safety protection messages, and will respond accordingly. The first appraisal is for threat [threat appraisal]. The threat appraisal has two components: severity and susceptibility. If, in the threat appraisal, the message recipient personally perceives the hazard to be of negligible consequence (low severity) or improbable (low susceptibility), any related message content encouraging a desired protection-oriented response or behavior will be rejected. If, however, the message passes the threat appraisal, the message recipient will next process the message's content for efficacy [efficacy appraisal]. The efficacy appraisal contains two components: self-efficacy and response efficacy. If the message recipient does not find the message's targeted behavior to be achievable (low self-efficacy) or efficacious (low response efficacy), the message recipient will engage in undesirable responses such as denial and avoidance in order to manage fear (described as “fear control” in the EPPM); this will be accompanied by message rejection. If, however, the efficacy appraisal is also passed, message acceptance will result, leading to adoption of the message's intended protective behavior change outcomes by taking desirable steps to minimize personal risk against the actual hazard (described as “danger control” in the EPPM).

https://doi.org/10.1371/journal.pone.0006365.g001

According to the EPPM, in order to be effective, messages must contain two parts: threat and efficacy. Message receivers sequentially perform two appraisals, first of threat and then of efficacy. The first portion of the message must convincingly transmit the existence of a threat, leading to concern on the part of the message receiver(s). The second portion of the message must convincingly transmit the existence of efficacious interventions/mitigations, especially those that are self-efficacious (i.e., able to be performed by the message receivers), leading to confidence. According to this model, the threat and efficacy components must be accepted by the message receivers to achieve the desired behavior or practice (at both individual and collective levels); this is termed “danger control” per the EPPM. If the threat portion is not accepted, the message is rejected. If the threat portion is accepted, but the efficacy portion is not, the acceptance of the threat portion triggers fear, which the message receivers attempt to manage (by rejecting the entire message); such a reaction is referred to as “fear control” per the EPPM.

Through the design and administration of an EPPM-centered survey of local health department personnel in three states, we aim to examine the relative influences of perceived threat and efficacy on public health workers' response willingness to pandemic influenza.

Methods

Results

Across the four health department regions, 1835 responses were collected for an overall response rate of 83%. Table 1 describes the composition of the four regions of respondents, and their catchment regional demographics based on U.S. Census data [22]. Most respondents were female (81%), over 40 years of age (72%), had at least a Bachelors' degree (73%), worked in their present organization for at least five years (64%), were in their profession for 10 or more years (58%), perceived having a role in responding to a public health emergency (84%), and had a family member dependent on them (67%). The regions were significantly different on most of these characteristics. The level of non-responses ranged from 1 to 2% across the four scenarios, considering all constructs and potential respondents for a given scenario. Similarly, the level of “don't know” responses ranged from 1.1 to 2.6%. Based on the criteria considered and the sensitivity analysis of how best to incorporate the “don't know” responses as a measure of attitudinal ambivalence in subsequent analyses, imputing these responses with the construct-specific “sample” median.was determined to be a reasonable approach.

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Table 1. Comparison of population and respondent characteristics by survey region.

https://doi.org/10.1371/journal.pone.0006365.t001

The overall percent agreement with the 20 pandemic influenza attitude and belief questions ranged from 94% for the perceived need for pre-event preparation and training, the severity of consequences, and the likelihood of being asked to report, to 74% for awareness of role-specific responsibilities (Table S1). Self-reported willingness to respond if required had 92% agreement, and self-reported willingness to respond if asked but not required had 86% agreement. For most of the questions, there was no significant difference in the percent agreement (‘positive’ responses) between regions as shown in Table S1. The three questions with the most inter-regional agreement for percent of positive responses (highest p-value) are the perceived likelihood of being asked to report to duty, self-reported willingness to respond if required, and the ability of the Health Department to provide timely information. Statistically significant inter-regional differences were observed for only three questions: self-reported willingness to respond if asked but not required, awareness of role-specific responsibilities, and skills for role-specific responsibilities. There was also no significant difference (p = 0.74) in the distribution of EPPM categories across the four regions (Table S1).

As a novel approach for understanding willingness to respond to a public health emergency, two relationships with EPPM were considered. The first approach considered whether demographic characteristics from Table 1 were related to the EPPM category assigned to a participant based on their responses to the four constructs noted in the statistical analysis section (Table 2). Region, age, educational level and expected role in emergency response were significant predictors of differences in the multinomial odds ratio (MOR) between EPPM categories. The largest significant MOR (95%CI) is 5.54 (3.36, 9.12), and indicated that the odds favoring being in the high threat/high efficacy EPPM category over the reference (low threat/low efficacy) category were 5.54 times higher for respondents having a perceived expected role in emergency response than for those not perceiving such a role.

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Table 2. Associations of demographic characteristics with categories of the Extended Parallel Process Model (EPPM) for a pandemic influenza emergency.

https://doi.org/10.1371/journal.pone.0006365.t002

A second set of analyses investigated the ability of EPPM categories to predict responses to the attitude and belief questions, with specific interest in the willingness-to-respond questions. Table 3 shows the results of these analyses and Table 4 shows these results adjusted for the demographic characteristics noted in Table 2. Overall the adjustment for demographic characteristics did not change the relationships of EPPM categories as predictors for any of the attitude/belief questions. The odds of a positive response to a question were significantly higher for the high threat/high efficacy (HT/HE) category than for the low threat/low efficacy (LT/LE) category. For example, the OR for answering positively to the perceived importance of one's role in the agency's overall response for the HT/HE category was 111.08 times larger than for the LT/LE category.

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Table 3. Associations of categories of the Extended Parallel Process Model (EPPM) with attitudes and beliefs regarding a pandemic influenza emergency (unadjusted for demographic characteristics).

https://doi.org/10.1371/journal.pone.0006365.t003

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Table 4. Associations of categories of the Extended Parallel Process Model with attitudes and beliefs regarding a pandemic influenza emergency (adjusted for demographic characteristics).

https://doi.org/10.1371/journal.pone.0006365.t004

A trend previously seen in region-specific analyses (reports to the agencies) and reiterated in Tables 3 and 4 was that the EPPM efficacy dimension tended to have a larger impact on a positive response to an attitude/belief question than the EPPM threat dimension. With respect to the reference (LT/LE) category, for example, the LT/HE category for self-reported willingness to respond if required had a higher OR of a positive response than the HT/LE category. This pattern, observed in 12 of the 16 construct questions, may suggest that the efficacy dimension has a larger impact on positive responses to the attitude and belief questions than the threat dimension.

Three of the 16 questions specifically addressed a respondent's willingness to respond. The OR (95%CI) of answering positively to self-reported willingness to respond if required was 31.7 (10.0, 100.51) times higher for the HT/HE group than for the LT/LE group. The comparable OR (95%CI) for self-reported willingness to respond if asked but not required was 9.52 (5.52, 16.44) and for willingness to respond regardless of severity was 11.22 (6.71, 18.74).

The vast majority (94%) of the respondents believed they will be called upon to respond to duty during an influenza pandemic (Table S1). However, follow up analyses indicate that health department employees who considered their individual roles to be important in the context of overall agency response efforts were, after adjustment for demographic characteristics, 8.45 (95%CI: 6.06, 11.77) times more likely to indicate they would report to duty during a pandemic even if it were severe. Ninety-one percent of the clinical staff felt their job during an influenza pandemic would be important, as compared with 85% among non-clinical staff, while only 73% of the non-clinical staff are aware of their role-specific responsibilities, as compared with 77% in the clinical staff.

Discussion

Willingness to respond is a critical component of effective public health system readiness and sustainability in emergencies. So far, on a national level, public health readiness and response efforts have focused nearly exclusively on enhancing ability, without specifically attending to willingness issues. Our study results suggest that this response willingness is not to be taken for granted in the public health arena. With some regional variation, overall 16% of the workers in 2006-7 were not willing to “respond to a pandemic flu emergency regardless of its severity”. This number is reassuring in contrast to that reported in previous studies, where higher percentages indicated they would not be willing to respond to an influenza pandemic [8], [10]. However, the workload in public health agencies during a pandemic will be so immense that “all hands on deck” will be required to tackle the resulting challenges, and significant changes in roles and responsibilities will be required. Reported unwillingness to respond by approximately 1 in 6 means that additional efforts are required to increase and sustain the proportion of local health department employees willing to respond. It simultaneously highlights the critical importance of understanding the reasons why some public health employees are unwilling to respond to a pandemic threat.

In this study, we address some of these gaps through systematic application of a behavioral model that addresses cognitive and emotional dynamics of response willingness attitudes. As a theoretical model based on decades of prior research on fear campaigns and health risk messaging, the EPPM describes how a sequence of threat appraisals (perceived severity and susceptibility) and efficacy appraisals (perceived response efficacy and self-efficacy) may influence behavioral responses to messages with fear content.

Using the EPPM, we can see how public health workers' individual degrees of perceived threat (‘concern’) and perceived efficacy (‘confidence’) influence their willingness to respond. Indeed, in line with our basic hypothesis, we have found that individuals who had a perception of high threat and high efficacy – i.e., those who fit a ‘concerned and confident’ profile in the EPPM analysis – had the highest declared self-reported willingness to respond (if required) rates to pandemic flu, which was 31.7 times higher than those fitting a ‘low threat/low efficacy’ EPPM profile.

Of the two basic components of the EPPM – perceived threat and perceived efficacy – the latter proves to be the more significant component in determining willingness in this scenario. Compared to the low threat/low efficacy reference category, low threat/high efficacy increases the willingness to respond if required almost 18-fold, while high threat/low efficacy is associated with less than a 3-fold increase. These results, assessed in 2006-7 following several years of increased awareness and high profile pandemic flu preparedness efforts at federal, state and local agencies, reveal a unique opportunity to induce change.

As any amount of additional assistance will make a difference in response to an influenza pandemic, the first step is to better educate public health workers as to their designated roles during this emergency scenario, and then motivate them with an understanding of why this role makes a difference. If a specific designated role cannot be predetermined, a set of potential roles have to be defined and adequately introduced to all relevant workers, up to a point at which they will feel confident in their ability to perform their duty, and perceive it as important.

Our results also suggest that downplaying the threat of the scenario to ‘calm’ the fears of the workers is not an advisable approach. A sense of threat is an important component in the worker's motivation to prepare for the event and to respond to it. It is important to note that 24% of the respondents did not perceive their work environment as safe, and 15% of the respondents felt they could not safely arrive to work. These issues must be an important component of the workers' training, and some assurance to their personal safety can and should be provided.

Certain limitations to the current study must be acknowledged. First, while we have strived to minimize social desirability bias in the construction and phrasing of the JH∼PHIRST instrument content, this survey-based study is not necessarily predictive of actual behavior during an event. Second, the findings from our study of local health department personnel may not necessarily translate to similar findings among responders in other cohorts such as hospital employees, EMS, or police; indeed, this is an area worthy of further comparative research study. Third, the imputation for “don't know” responses may result in narrower confidence intervals for the odds ratio estimates; however, our intent is to provide a relative perspective on willingness to respond and the factors that influence it for a given health department and to identify patterns of attitudes that may influence effectiveness of health departments in emergency situations. Despite these caveats, however, ascertaining local health department workers' dispositions toward fulfilling pandemic flu response expectations nonetheless has value for current local public health agency readiness and response efforts and related training needs assessments.

In a pilot study of local Maryland public health personnel in 2005 [8], we illustrated that risk perception influences peripheral to the actual event – such as perceived importance of one's role in an agency response – can markedly affect willingness-to-respond rates. The results at the time indicated that nearly half of the workers noted they are unlikely to respond to duty during a pandemic emergency. In the US, efforts put into planning, training, exercising and increasing awareness of public health roles in disaster response since the introduction of the Pandemic and All-Hazards Preparedness Act [23], as well as the federal, state, and local resources provided in support of the same, may explain some of the improvement in the willingness to respond rates between the surveys. It should be noted, though, that significant changes in the phrasing of the questions from the pilot study do not allow direct comparison of the responses to the current larger-scale multi-state online survey.

In conclusion, our findings point to the EPPM as a useful framework to inform nuanced assessments of levels of – and gaps in – willingness to respond within the local public health infrastructure. Our data indicate that ‘concerned and confident’ local public health employees are most likely to be willing to respond to an influenza pandemic. This finding may allow public health agencies to design, implement, and evaluate training programs focused on emergency response willingness in health departments.

Supporting Information

Acknowledgments

The authors wish to acknowledge and thank participating public health departments in Minnesota, Ohio, and West Virginia and their staff for taking part in this research study.