ABSTRACT
The 2014–2016 Ebola virus outbreak in West Africa led to advances in the development of vaccines against Ebola. This study examined factors associated with willingness to pay for an Ebola vaccine among a U.S. national sample during the recent Ebola outbreak. From April 30–May 8, 2015, a national survey was conducted using the GfK Group's KnowlegePanel®. Main outcome measures included willingness to pay at least $1; more than $50; and more than $100 for an Ebola vaccine. Analyses were conducted using weighted multivariable logistic regression. Among participants (N = 1,447), 583 (40.3%) would not pay for an Ebola vaccine; 864 (59.7%) would pay at least $1. Among those willing to pay at least $1: 570 (66.0%) would pay $1–50; 174 (20.1%) would pay $51–100; and 120 (13.9%) would pay more than $100. Willingness to pay at least $1 for an Ebola vaccine was associated with international travel; interest in getting an Ebola vaccine; and beliefs that the U.S. government should spend money to control Ebola and assume worldwide leadership in confronting emerging epidemics. Willingness to pay more than $50 was associated with similar variables. Willingness to pay more than $100 was associated with international travel; interest in getting an Ebola vaccine; information seeking; and beliefs that the U.S. government should assume worldwide leadership in confronting emerging epidemics. International travel and interest in an Ebola vaccine were key predictors of willingness to pay across all price points. Understanding willingness to pay for vaccines against emerging infectious diseases remains critical.
Introduction
From 2014–2016, West Africa experienced the largest outbreak of Ebola virus disease (Ebola) in history — infecting over 28,000 people and killing over 11,000.Citation1 The severity of this outbreak, declared a Public Health Emergency of International Concern (PHEIC) by the World Health Organization (WHO) in August of 2014,Citation2 has led to accelerated Ebola vaccine research and clinical trials.Citation3-9 Recently, findings from the rVSV-ZEBOV vaccine phase III clinical trial indicated 100% vaccine efficacy, bringing an Ebola vaccine one-step closer to reality.Citation7 Considered a global priority,Citation6,Citation8 development of an Ebola vaccine would be of significant benefit to people living in West Africa and other regions at increased risk for Ebola virus outbreaks.
An Ebola vaccine might also be of benefit certain groups of people in the United States, such as health care workers treating Ebola patients, personnel assisting with outbreak response, and travelers to Ebola-affected areas. It is unlikely that an Ebola vaccine would greatly benefit the U.S. population in general, as the epidemiological toll of the 2014–2016 Ebola epidemic in the United States was minimal. Yet while only four cases were reported nationally,Citation10,Citation11 the epidemic garnered extensive media coverage, leading to a national contagion of fear.Citation12 The U.S. “Fearbola”Citation13 phenomenon provides a unique opportunity to explore factors that might impact willingness to pay for an Ebola vaccine in the United States.
Willingness to pay for vaccines is an important indicator of public perception and demand,Citation14,Citation15 which has been identified as a major factor in influencing vaccine policy and innovation.Citation16 Thus, the introduction of a new vaccine, especially one relying on self-pay, should examine whether the public is willing to purchase the novel vaccine. Most studies of willingness to pay for vaccines have focused on endemic diseases in both developing and developed countries. Studies gauging willingness to pay for vaccines targeting diseases such as dengue,Citation15,Citation17-19 pneumococcal pneumonia,Citation20,Citation21 seasonal influenza,Citation20,Citation22,Citation23 and human papillomavirus (HPV)Citation24-26 have found a range of variables to be associated with willingness to pay, including demographic, socioeconomic, attitude, and vaccine attribute factors. Additionally, a systematic review found that willingness to pay for vaccines varies depending on vaccine type and disease severity, with consumers willing to pay more for vaccines against diseases with high morbidity and mortality.Citation27 Several studies have examined willingness to pay for an Ebola vaccine among high priority populations (e.g., health care workers) and general populations of Ebola-affected countries in West Africa; however, findings may not be relevant to the U.S. domestic context.Citation28-30
The purpose of this study was to assess willingness to pay for an Ebola vaccine among a U.S. national sample during the height of the 2014–2016 Ebola epidemic in West Africa. Findings may help shed light on the trade-off that Americans are willing to make regarding personal wealth versus perceived risk of death or disease during a highly publicized infectious disease epidemic occurring elsewhere in the world.
Results
A total of 1471 participants completed the survey. Of those, 30 persons did not answer the question about willingness to pay for an Ebola vaccine. Only participants who answered the question regarding willingness to pay for an Ebola vaccine (n = 1,447) were included in analyses. Among participants (N = 1,447), 583 (40.3%) would not pay out of pocket for an Ebola vaccine; 864 (59.7%) would pay at least $1. Among those willing to pay at least $1: 570 (66.0%) would pay $1–50; 174 (20.1%) would pay $51–100; and 120 (13.9%) would pay more than $100.
In bivariate analyses, the proportion of participants willing to pay at least $1 for an Ebola vaccine was higher among those with higher levels of education, higher levels of income, history of international travel in the past 12 months, and interest in getting an Ebola vaccine (). Participants who were willing to pay at least $1 for an Ebola vaccine had higher mean scores on scales measuring Ebola-related knowledge, Ebola-driven behaviors (information seeking and hand hygiene), perceived susceptibility to Ebola, perceived severity of Ebola, support for U.S. government spending to control Ebola, support for U.S. government intervention to control Ebola internationally, and support for U.S. government leadership in confronting emerging epidemics worldwide.
Table 1. Characteristics of Ebola survey participants – United States, 2015 (N = 1447).
In weighted multivariable analyses, willingness to pay at least $1 for an Ebola vaccine was associated with international travel in the past 12 months (aOR = 2.12; 95% CI = 1.46, 3.09; p<.001), interest in getting an Ebola vaccine (aOR = 6.72; 95% CI = 5.02, 8.99; p<.001), beliefs that the U.S. government should spend money to control Ebola (aOR = 1.12; 95% CI = 1.06, 1.19; p<.001), and beliefs that the U.S. government should assume worldwide leadership in confronting emerging epidemics (aOR = 1.09; 95% CI = 1.03, 1.16; p = .003) ().
Table 2. Final multivariable models of factors associated with willingness to pay for an Ebola virus vaccine, determined using stepwise logistic regression with forward selection, among a U.S. National Sample – United States, 2015.
Willingness to pay more than $50 for an Ebola vaccine was associated with similar variables: international travel in the past 12 months (aOR = 3.46; 95% CI = 2.43, 4.92; p<.001), interest in getting an Ebola vaccine (aOR = 3.63; 95% CI = 2.73, 4.83; p<.001), beliefs that the U.S. government should spend money to control Ebola (aOR = 1.09; 95% CI = 1.02, 1.18; p = .016), and beliefs that the U.S. government should assume worldwide leadership in confronting emerging epidemics (aOR = 1.09; 95% CI = 1.02, 1.17; p = .010).
Among the full sample, willingness to pay more than $100 was associated with international travel in the past 12 months (aOR = 3.07; 95% CI = 1.95, 4.84; p<.001), interest in getting an Ebola vaccine (aOR = 3.63; 95% CI = 2.23, 5.05; p<.001), information seeking about Ebola (aOR = 1.18; 95% CI = 1.04, 1.35; p<.010), and beliefs that the U.S. government should assume worldwide leadership in confronting emerging epidemics (aOR = 1.13; 95% CI = 1.03, 1.23; p = .007). Among participants who would pay at least $1 for an Ebola vaccine, willingness to pay more than $100 was associated with international travel in the past 12 months (aOR = 2.39; 95% CI = 1.50, 3.81; p<.001), interest in getting an Ebola vaccine (aOR = 1.66; 95% CI = 1.10, 2.51; p<.017), and information seeking about Ebola (aOR = 1.22; 95% CI = 1.08, 1.39; p = .002). Compared to participants who lived in the Northeast, participants who lived in the Midwest (aOR = 0.50; 95% CI = 0.26, 0.93; p = .028) or South (aOR = 0.50; 95% CI = 0.28, 0.85; p = .011), were less likely to be willing to pay more than $100.
Discussion
This study provides novel information regarding willingness to pay for an Ebola vaccine among a U.S. national sample during the 2014–2016 epidemic in West Africa. While previous studies have assessed willingness to pay for an Ebola vaccine in West Africa,Citation28-30 findings from these studies are not generalizable to the U.S. population. In the present study, approximately 60% of participants were willing to pay at least $1 for an Ebola vaccine, despite minimal risk of an outbreak in the United States. Willingness to pay is an indicator of the perceived value placed on an Ebola vaccine,Citation14 suggesting U.S citizens would value an Ebola vaccine during an epidemic — even if the epidemic primarily affected countries in an international setting. This finding has potential implications for Ebola vaccine financing, particularly for self-pay. Vaccine availability in the U.S. could potentially offset costs in areas such as West Africa, where the need is great, but the ability to pay is limited.Citation31
Findings indicated two variables, international travel in the past 12 months and interest in an Ebola vaccine, were associated with willingness to pay across all price points. Participants with a history of international travel might be more willing to pay for an Ebola vaccine, even in excess of $100, because they are concerned about travel-related infectious disease risks. International travel is a common risk factor for infectious disease acquisition and importation to the United States.Citation32 Once an Ebola vaccine is licensed, vaccinating international travelers against Ebola, particularly those working in health-related settings,Citation33 might be an effective strategy to ensure the safety of U.S. travelers and reduce the risk of the Ebola introduction nationally.
The finding that interest in an Ebola vaccine was associated with willingness to pay out of pocked for an Ebola vaccine was expected. If an individual feels at risk for Ebola, then they would value being protected against Ebola; and logically be willing to pay money for a vaccine. Of note, participants’ interest in getting an Ebola vaccine was not synonymous with being willing to pay for a vaccine. In fact, over 400 participants did not express interest in getting an Ebola vaccine, yet would be willing to pay at least $1 for a vaccine. There are several potential explanations for this result. First, this finding could reflect a realistic assessment of Ebola risk. Participants who were not interested in getting an Ebola vaccine might have accurately assessed that they were not likely to get Ebola in the United States, and therefore not interested in getting a vaccine; however, they would be willing to pay a nominal amount (e.g., $1) for an Ebola vaccine if offered. Second, this finding might reflect consistency with a study of acceptability and willingness to pay for an Ebola vaccine in Nigeria.Citation28 In that study, many participants would only accept an Ebola vaccine after observing other people receive the vaccine first. Similarly, participants in the present study might not have been interested in getting an Ebola vaccine unless they could be sure that it was safe and effective, as safety is a common reason for not be willing to get a vaccine.Citation34 Yet, if they were to get a vaccine, they would be willing to pay out of pocket for it. Third, this finding could reflect the hypothetical nature of the questions being asked. There could have been unmeasured factors, including vaccine characteristics (e.g., safety, efficacy, side-effects)Citation15,Citation17,Citation24 and timeliness of vaccine availability,Citation35 which might have impacted participants’ answers regarding vaccine interest and willingness to pay.
Another important finding is that national threat beliefs, including beliefs that the U.S. government should spend money to control Ebola and beliefs that the U.S. government should assume worldwide leadership in confronting emerging epidemics, were significantly associated with willingness to pay for an Ebola vaccine at multiple price points. This finding is consistent with previous research reporting an association between national threat beliefs and interest in an Ebola vaccine,Citation33 indicating that people who consider Ebola a national priority might consider it a personal priority, as well. This finding might also reflect an appreciation of the fact that multiple levels of action are necessary to protect individuals against emerging infectious diseases, including interventions at the individual level (e.g., vaccination), the national level (e.g., enhancing surveillance and preventing disease importation), and the international level (e.g., developing collaborations to stem emerging infectious disease epidemics at their source).Citation36
Limitations
This study has several limitations. First, questions about the Ebola vaccine were hypothetical; thus, it is unknown if findings would apply to an actual vaccine. Willingness to pay for an actual vaccine would likely depend on cost, as well as other vaccine-related factors. Second, this study did not account for vaccine characteristics (e.g., safety and efficacy) which have been demonstrated to impact willingness to pay for other vaccines.Citation15,Citation17,Citation24 Third, this study was conducted during the height of the Ebola epidemic in West Africa, and “Fearbola”Citation13 epidemic in the United States. It is unclear if findings would be similar under non-outbreak circumstances. Fourth, this study relied on self-report; thus social desirability bias might have influenced participant responses. Finally, the survey did not collect data regarding participants’ knowledge or attitudes regarding costs of a typical vaccine, such as the seasonal influenza vaccine. Thus, it is unclear how participants’ willingness to pay for an Ebola vaccine compares to willingness to pay for other vaccines.
Conclusion
To our knowledge, this study is the first to assess willingness to pay for an Ebola vaccine in the United States. This study provides valuable information about characteristics of individuals willing to pay for an Ebola vaccine during the height of the 2014–2016 Ebola epidemic, a highly publicized epidemic in an international setting. Findings indicated that international travel and interest in an Ebola vaccine were the most salient predictors of willingness to pay across all price points, and might be relevant in the event of future emerging infectious disease threats. Once an Ebola vaccine is licensed, further assessment of willingness to pay will be critical. Future studies should examine willingness to pay for vaccines against emerging infectious diseases both in the United States and abroad.
Materials and methods
The survey methodology for this study has been previously described.Citation33 Briefly, a nationally representative survey of U.S. adults was conducted from April 30–May 8, 2015, using the GfK Group's KnowlegePanel®. The KnowlegePanel® survey employed a probability-based web panel using an address-based sampling methodology, which covers households regardless of their phone status. This allowed for a diverse and representative household-based sample, including hard-to-reach individuals, with oversampling from census block groups within high-density minority communities. Data weights were employed so that the sample distribution matched that of the U.S. adult population. The target population consisted of non-institutionalized, English-language survey-taking adults, age 18 and over, residing in the United States. This study was approved by the IRB at the researchers’ institution.
Measures
The main outcome measures were willingness to pay at least $1; more than $50; and more than $100 for an Ebola vaccine. Participants were asked, “How much would you pay out of pocket for an Ebola vaccine if your health insurance did not cover the cost of the vaccine?” Answer choices included: $0 (I would not pay for an Ebola vaccine); $1–$50; $51–$100; $101–$150; $151–$200; more than $200. Due to small numbers of respondents, the last three response options were combined into one category: more than $100.
Predictor variables included background factors (age, sex, race, education, income, region, and history of international travel in the past 12 months); interest in getting an Ebola vaccine (indicated by responding “very likely” or “fairly likely” when asked “How likely would you be to get a vaccine that would prevent you from getting Ebola?”); Ebola-related knowledge; Ebola-related behaviors (information seeking and hand hygiene); and Ebola-related attitudes (personal and national threat beliefs). Psychometric properties of Ebola-related knowledge, behavior, and attitude scales among participants who answered the question regarding willingness to pay for an Ebola vaccine are presented in .
Table 3. Items and measurement characteristics for scale variables among a U.S. National Sample (N = 1,447) — United States, 2015.
Analyses were conducted with SPSS (version 24). Cronbach alphas were calculated for scale variables to measure internal consistency, as an indicator of reliability. Chi-square tests (for dichotomous and categorical variables) and t-tests (for continuous variables) were conducted to assess differences in characteristics among participants willing to pay at least $1 for an Ebola vaccine compared to participants not willing to pay at least $1 for an Ebola vaccine. Unadjusted logistic regressions were conducted to assess the association between predictor and outcome variables. All variables significant at the p = .10 level in unadjusted regression analyses were included as potential independent variables in weighted multivariable analyses. Stepwise logistic regression with forward selection was used to determine the best combination of variables associated with willingness to pay for an Ebola vaccine using the most parsimonious model. Willingness to pay more than $100 was assessed among the full sample and among participants willing to pay at least $1.
Disclosure of potential conflicts of interest
No potential conflicts of interest were disclosed.
Acknowledgments
The authors wish to thank Chris Martin, from the Department of Sociology, Emory University, and Nahiri Patel, from the Department of Behavioral Sciences and Health Education, Rollins School of Public Health, Emory University, for their tremendous assistance with this study.
Related Research Data
References
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