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Preferences for health outcomes associated with Group A Streptococcal disease and vaccination
Health and Quality of Life Outcomes volume 8, Article number: 28 (2010)
A 26-valent Group A Streptococcus (GAS) vaccine candidate has been developed that may provide protection against pharyngitis, invasive disease and rheumatic fever. However, recommendations for the use of a new vaccine must be informed by a range of considerations, including parents' preferences for different relevant health outcomes. Our objectives were to: (1) describe parent preferences for GAS disease and vaccination using willingness-to-pay (WTP) and time trade-off (TTO) methods; and (2) understand how parents' implied WTP for a quality-adjusted life year (QALY) gained might vary depending on the particular health outcome considered (e.g. averted GAS disease vs. vaccine adverse events).
Telephone interviews were conducted with parents of children diagnosed with GAS pharyngitis at 2 pediatric practice sites in the Boston metropolitan area. WTP and TTO (trading parental longevity for child's health) questions for 2 vaccine and 4 disease-associated health states were asked using a randomly selected opening bid, followed by a 2nd bid and a final open-ended question about the amount willing to pay or trade. Descriptive analyses included medians and interquartile ranges for WTP and TTO estimates. The Wilcoxon signed-rank test was used to assess differences in WTP/QALY values for vaccine adverse events vs. disease states.
Of 119 respondents, 100 (84%) and 96 (81%) provided a complete set of responses for WTP and TTO questions, respectively. The median WTP and discounted (at 3% per year) TTO values to avoid each health state were as follows: local reaction, $30, 0.12 days; systemic reaction, $50, 0.22 days; impetigo, $75, 1.25 days; strep throat, $75, 2.5 days; septic arthritis, $1,000, 6.6 days; and toxic shock syndrome, $3,000, 31.0 days. The median WTP/QALY was significantly higher for vaccine adverse events (~$60,000/QALY) compared to disease states ($18,000 to $36,000/QALY).
Parents strongly prefer to prevent GAS disease in children compared to vaccine adverse events. However, implied WTP/QALY ratios were higher for the prevention of vaccine adverse events. Regret for errors of commission vs. omission may differ and should be considered by vaccine policymakers.
Group A Streptococcus (GAS) is responsible for up to 2.6 million cases of pharyngitis in children each year and 1.1 million cases in adults in the U.S., with an estimated economic burden of $224-539 million annually due to GAS pharyngitis [1, 2]. In addition, infection with GAS causes up to 9,700 cases of invasive disease and 1,300 deaths annually [3, 4]. The clinical spectrum of invasive GAS disease is broad and may include bacteremia, pneumonia, septic arthritis, osteomyelitis, meningitis, necrotizing fasciitis, or streptococcal toxic shock syndrome [4–7].
Recently, a 26-valent GAS vaccine candidate was developed that may provide protection against pharyngitis, invasive disease and rheumatic fever [8, 9]. Such a vaccine may reduce the burden of GAS disease by up to 85% in the U.S [4, 10, 11]. However, parental preferences regarding the prevention of disease vs. the risk for minor vaccine adverse events should be explicitly considered before recommending widespread use of a GAS vaccine. This is particularly relevant as concerns about vaccine safety have become prominent, and the number of parents refusing to vaccinate their children continues to grow as perceptions about the risks of vaccination may outweigh perceived benefits [12–15].
Estimating preferences for childhood vaccination programs has been challenging for several reasons. First, parents often serve as proxy respondents for young children, raising concerns about how to distinguish the child's well-being from the parent's altruism [16–18]. However, since parents are responsible for decision-making about vaccinating their own children, and young children are often unable to provide quantitative assessments of their preferences, the choice of parents as a proxy may be appropriate. Second, while many of the older childhood vaccines have been focused on preventing chronic disability and death (e.g. neurologic disability and death after Haemophilus influenzae type b infection, paralysis and death after polio infection), newer vaccines may target health conditions that are temporary in duration (e.g. otitis media and bacteremia in pneumococcal infection) [19, 20]. Health states that are described as short-term may be valued differently than the same health states as chronic conditions [21–23]. Third, off-the-shelf utilities do not exist for many of the short-term health conditions, necessitating a formal assessment of preferences when implementing a new vaccination program. Finally, although many childhood vaccination programs have historically been found to be cost-saving, the higher prices associated with several newer vaccines and rising emphasis on concerns about vaccine safety require explicit examination of the costs and health consequences of new programs [12–15]. An empirical assessment of the willingness-to-pay for a quality-adjusted life year gained may provide important information for decision-makers in the context of national vaccine policy.
Thus, our objectives were to: (1) describe parent preferences for GAS disease and vaccination using willingness-to-pay (WTP) and time trade-off (TTO) methods, and (2) understand how parent's implied WTP for a quality-adjusted life year (QALY) gained might vary depending on the particular health outcome considered (e.g. averted GAS disease vs. vaccine adverse events).
Telephone interviews were conducted with parents of children diagnosed with GAS pharyngitis at two pediatric practice sites in the Boston metropolitan area. We identified 236 potentially eligible episodes of GAS pharyngitis among children who were seen at one urban and one suburban practice for urgent care visits from October 1, 2005 to January 25, 2006. Families were considered eligible for the study if the child or adolescent was less than 18 years of age, had symptoms consistent with strep throat and a confirmed diagnosis of GAS pharyngitis with a positive rapid strep test or throat culture.
Fifty-two cases were excluded from the study for the following reasons: incorrect address or telephone number (22), child already had a sibling enrolled in the study (12), child previously enrolled in the study (7), taken to the doctor by someone other than a parent or guardian (7), parent or guardian did not understand that child had GAS pharyngitis (3), and parent or guardian was non-English speaking (2). Of the 236 potentially eligible children seen during the study period, 135 (57%) parents agreed to participate in the study. Among these parents, 16 were initially selected to pilot the preferences survey, and 119 parents received the final survey.
The telephone survey included questions about parent preferences for avoiding short-term health states associated with GAS disease and vaccination in their child including impetigo, strep throat, septic arthritis, and streptococcal toxic shock syndrome (Please see Additional File 1). Parents were asked both willingness-to-pay (WTP) and time trade-off (TTO) questions about each health state. In addition, information was collected on demographics, duration of illness, medical costs, and non-medical costs associated with episodes of GAS pharyngitis in children.
For WTP questions, respondents were asked "Using money that is available to you today, think about how much money you would be willing to pay to prevent your children from having this condition." The framing of the question in terms of currently available resources was intended to elicit the amounts that individuals would actually pay in order to enhance the validity of the study; a disadvantage of this approach is that higher respondent incomes would likely be associated with higher WTP . Interviewers presented respondents with a randomly selected opening bid (high, intermediate, low) for each health state (Please see additional File 2). If respondents were willing to pay the opening bid, they were asked if they would be willing to pay a higher amount to avoid the health state in question. If respondents were not willing to pay the opening bid, they were asked if they would be willing to pay a lower amount. After their response to the subsequent bid, interviewers asked, "What is the most you would be willing to pay?".
For TTO questions, respondents were instructed as follows: "Think about how many hours or days you would be willing to give up from the end of your life in order to prevent your child from having this condition." Of note, all health conditions were described as being short-term and the duration of each health state was described, ranging from 2 days to 3 weeks. Similar to WTP, respondents were given a high, intermediate, or low opening bid in terms of hours or days traded to prevent illness in their child. After answering, a subsequent bid was offered and then parents were asked, "What is the most you would be willing to trade?" Because parents were asked to trade time from the end of their lives, we estimated the impact of alternative assumptions about discounting (0-5%) of future health outcomes.
Final responses to the binary plus follow-up questions for WTP (N = 100) and TTO (N = 96) are presented as medians and interquartile ranges (IQRs), in order to minimize the impact of outliers, particularly since the distributions of responses were skewed. Individuals who either refused to answer (N = 7 for WTP; N = 12 for TTO) or did not provide an open-ended response for each of the health states (N = 12 for WTP; N = 11 for TTO) were excluded from our primary analysis, in order to accommodate analysis of individual rankings of the set of health states. In a secondary analysis, we also estimated predicted values for missing, interval or censored responses for each health state using a multivariable interval regression model that included age, gender, and income as covariates. Comparison of results including these predicted values allowed us to understand the impact of missing data on the primary analyses. To understand the impact of income on WTP estimates, we calculated Spearman's rank correlation coefficients.
Disutilities for short-term health states were calculated using a previously published method . The numerator is the difference between the discounted stream of normal life expectancy (LE) for the respondent, in years, and the discounted stream of shortened LE, calculated as (1/r)*(1-e(-r)*(LE of respondent)) - (1/r)*(1-e(-r)*(LE of respondent - time traded)), where r is the discount rate. We interpret this expression as the number of QALYs given up by the parent to avoid having the child live with the health outcome under consideration. The denominator is the duration of the health state for the child that begins at the present time, discounted accordingly for consistency, calculated as (1/r) * [1-e(-r) (duration of health state)]. We assumed that the maximum amount of discounted time traded from the end of the respondent's life could not exceed the (discounted) duration of the health state, which anchors the lowest time tradeoff value at zero. To calculate WTP for a QALY, we divided the WTP response by the same expression used in the numerator of the disutility calculation above, as this represents the QALY equivalent for the health outcome:
Individual values for the WTP/QALY ratio were calculated and medians and interquartile ranges are reported for each of the six health states described. Values for individuals who did not trade any time to avoid illness (i.e. denominator equals zero) were excluded for that particular health state for WTP/QALY calculations, although they were included in descriptive analyses for TTO responses. The Wilcoxon signed-rank test was used to test for differences in WTP/QALY values for each matched pair of health states. Additionally, 95% bias-corrected confidence intervals were calculated for the median WTP/QALY for each health state using bootstrapping with 10,000 re-samples. We chose to use the non-parametric bootstrapping method to derive our bias-corrected confidence intervals, since it makes no assumptions about the distribution of WTP/QALY value.
Our study population included 119 parents of children diagnosed with GAS pharyngitis. Respondents were mostly female (91%), had at least some college education (80%), and had annual household incomes greater than or equal to $80,000 (50%). (Table 1) Among these participants, 100 (84%) and 96 (81%) individuals provided open-ended responses to the WTP and TTO questions, respectively, although 112 (94%) and 107 (90%) individuals provided at least some interval data for WTP and TTO questions. Comparing those who provided open-ended responses to those who did not, there were no differences in age, gender, educational level, or race/ethnicity. Respondents who refused to report their annual household income were significantly less likely to provide complete, open-ended responses to WTP (p = 0.002) and TTO (p = 0.001) survey items.
The median WTP values for local and systemic reactions associated with vaccination were $30 and $50, respectively (Table 2). Mild disease states associated with GAS infection such as impetigo and strep throat were associated with higher median WTP values. Parents were willing to pay the highest amounts to avoid severe disease such as septic arthritis ($1,000) or streptococcal toxic shock syndrome ($3,000). Nonetheless, some respondents reported they would not be willing to pay any amount of money ($0) to avoid the following health states: local reaction (12%), systemic reaction (6%), impetigo (4%), and strep throat (3%). Income was significantly correlated with WTP estimates for the most severe health states such as septic arthritis (ρ = 0.286, p = 0.003) and streptococcal toxic shock syndrome (ρ = 0.289, p = 0.003); however, there was no correlation between income and WTP values for local reaction, systemic reaction, impetigo, or strep throat. In secondary analyses that included predicted values for missing, interval, or censored data, the median WTP was the same or nearly the same for all states: local reactions ($30), systemic reactions ($50), impetigo ($75), strep throat ($85), septic arthritis ($1,000), and toxic shock syndrome ($3,233).
We calculated the present value of the median number of days traded assuming discount rates of 0%, 3%, and 5% (Table 2). If we assumed that respondents discounted future time at 3% per year, the median number of days traded for a local reaction was 0.12 days compared to 31.0 days traded to avoid a case of toxic shock syndrome (Table 2). Of note, some respondents were unwilling to trade any time (zero days) for the following health states: local reaction (22%), systemic reaction (18%), impetigo (17%), strep throat (14%), septic arthritis (4%), and toxic shock syndrome (3%). For these short term health states, median utilities were calculated for local reactions (0.942), systemic reactions (0.892), impetigo (0.959), strep throat (0.925), septic arthritis (0.687), and toxic shock syndrome (0.0). Accounting for the duration of each health state (which ranged from 2 days to 3 weeks), median estimates for QALYs in the year of the infection were 0.9997 for local reactions, 0.9994 for systemic reactions, 0.9986 for impetigo, 0.9977 for strep throat, 0.9793 for septic arthritis, and 0.9063 for toxic shock syndrome. In a secondary analysis, the inclusion of predicted estimates for missing, interval or censored variables provided similar estimates for days traded discounted at 3%: local reactions (median 0.17; IQR [0.04-0.44]), systemic reactions (median 0.24; IQR [0.06-0.54]), impetigo (median 0.56; IQR [0.13-1.99]), strep throat (median 0.75; IQR [0.27-3.5]), septic arthritis (median 10.5; IQR [3.5-30.5]), and toxic shock syndrome (median 41.5; IQR [8.3-134]).
WTP per QALY
The median implied WTP per QALY and 95% confidence intervals were calculated across individuals for each health state (Figure 1). Local reactions had a significantly higher WTP per QALY when compared to strep throat (p = 0.006), septic arthritis (p = 0.029), or toxic shock syndrome (p = 0.034). The median WTP per QALY was also significantly higher for systemic reactions compared to any of the health states associated with GAS disease (impetigo, p = 0.012; strep throat, p = 0.033; septic arthritis, p = 0.008; toxic shock syndrome, p = 0.022). When we included WTP per QALY estimates based on predicted values, the median amount remained significantly higher for local reactions vs. septic arthritis (p = 0.019), local reactions vs. toxic shock syndrome (p = 0.044), systemic reactions vs. strep throat (p = 0.010), systemic reactions vs. septic arthritis (p = 0.008), and systemic reactions vs. toxic shock syndrome (p = 0.009).
Parents were willing to trade more time and money to avoid severe health states (i.e. septic arthritis, toxic shock syndrome) associated with GAS disease vs. mild GAS disease states (i.e. impetigo, strep throat) or minor vaccine adverse events. The relative strength of preference to avoid disease states, particularly severe conditions, compared to minor vaccine adverse events has been previously demonstrated [20, 21]. Interestingly, however, many vaccine cost-effectiveness analyses have not typically considered the potential disutility associated with vaccine adverse events in program evaluations , perhaps because historically vaccines were life-saving, so these minor adverse events were negligible compared to the large overall benefits. As newer vaccines focus more on the prevention of morbidity, rather than mortality, parental and patient preferences to avoid both disease states and vaccine adverse events should be explicitly considered.
Prior studies have estimated parental WTP to avoid minor vaccine adverse events such as local or systemic reactions. A 1999 study  reported a median parental WTP of $10 to $25 to reduce an infant's pain and emotional distress from childhood vaccination, while a study in 2001 reported a WTP of $25 to prevent fever and fussiness in young children after pneumococcal conjugate vaccine administration . Another study conducted in 2002 examined parental WTP to avoid local and systemic reactions in adolescents, and found median estimates of $3 and $13, respectively . Parents in our study reported slightly higher WTP values to prevent local ($30) and systemic ($50) reactions after a GAS vaccine, which may reflect differences in health state descriptions across studies, different considerations by parents depending on the age of the child (infant vs. toddler vs. adolescent), differences in the socioeconomic status of our population, inflation, or changes in the overall societal context regarding vaccine safety.
Empirically calculating the implied WTP per QALY may provide insight into the true societal WTP for gains in health, which may be preferred to using the persistent benchmark of $50,000 to $100,000 per QALY saved . Although the standard approach in cost-effectiveness analysis relies on benchmarks for high-value interventions using the same threshold value for the WTP per QALY for all interventions, we observe substantial differences in the WTP per QALY to avoid different health states. In our study, parents were willing to pay more per incremental health gain to avoid vaccine adverse events (~$60,000 per QALY) compared to avoiding health states associated with GAS disease (~$18,000 to $36,000 per QALY). If these differences relate to true variability in the relative importance parents place on different types of outcomes, after controlling for the duration and severity of these outcomes, an important implication is that increased attention should focus on minimizing potential complications in healthy individuals. While it has previously been shown that treatment interventions are strongly preferred by society to preventive interventions [27, 28], we are not aware of any studies that have explicitly compared preferences regarding vaccine adverse events vs. disease prevention.
Our findings that parents have a greater WTP per QALY for preventing vaccine adverse events compared to disease may be indicative of how individuals experience regret. An action, such as vaccinating a child, resulting in a potential adverse event may generate more regret than an inaction (i.e. refusing to vaccinate a child), even if a child becomes ill with a preventable disease [29–31]. This phenomenon is often characterized in terms of the distinction between "acts of commission" and "acts of omission", which is particularly relevant in the case of vaccination . Parents may feel more guilt over agreeing to give a vaccine to their child that might cause harm, particularly in the short term, when compared to not vaccinating their child who by random chance develops disease. This may be reinforced by the changing perception of the risk-benefit balance by society, where fewer individuals have direct experience with vaccine-preventable diseases, furthering the intuitive response by some parents to focus more on vaccine safety and concerns about harming their child . Further exploration of how regret for errors of commission and omission may influence parental preferences in vaccination programs is needed, particularly as new vaccines are recommended for use.
Our study has several limitations. First, our study population was relatively small and limited to parents of children who have experienced GAS pharyngitis. Consideration should be given to obtaining community values regarding GAS vaccination and disease . Second, parents may not have had a complete understanding of the implications of these health states since our descriptions were brief and interviews were conducted by phone. As with any TTO, since parents were trading time from the end of their life, they may have assumed that they were trading time from a worse health state than their present condition and potentially have biased our TTO disutility estimates upward . Third, anchoring bias may have occurred for our WTP and TTO estimates since we presented individuals with an initial opening bid that may have affected subsequent responses, although we did attempt to minimize this by randomizing among 3 different starting bids . Fourth, missing or incomplete responses may have biased our WTP and TTO estimate in either direction. In a secondary analysis, however, our findings did not change significantly with the inclusion of predicted estimates for these individuals based on their characteristics. Fifth, WTP per QALY was inferred rather than directly elicited. Additionally, the pattern of declining WTP per QALY estimates for more severe health states may be due in part to the insensitivity to scale in WTP [37, 38]. Finally, another key limitation of this study is that information was not available regarding parental refusal or deferral on any of their child's vaccines, thus we could not validate the WTP per QALY estimates with actual changes in behavior patterns.
Our findings suggest that parents prefer to prevent GAS disease in children compared to preventing minor vaccine adverse events, but that parents are also willing to pay more per QALY gained to prevent vaccine adverse events. Parental preferences should be incorporated in decision-making by policymakers when implementing new vaccination programs in the U.S.
Linder JA, Bates DW, Lee GM, Finkelstein JA: Antibiotic treatment of children with sore throat. Jama 2005,294(18):2315–2322. 10.1001/jama.294.18.2315
Pfoh E, Wessels MR, Goldmann D, Lee GM: Burden and economic cost of group A streptococcal pharyngitis. Pediatrics 2008,121(2):229–234. 10.1542/peds.2007-0484
CDC: Active bacterial core surveillance report (ABCs), emerging infections program network group A streptococcus. 1997. [http://www.cdc.gov/abcs/reports-findings/survreports/gas05.html]
O'Loughlin RE, Roberson A, Cieslak PR, Lynfield R, Gershman K, Craig A, Albanese BA, Farley MM, Barrett NL, Spina NL, et al.: The epidemiology of invasive group A streptococcal infection and potential vaccine implications: United States, 2000–2004. Clin Infect Dis 2007,45(7):853–862. 10.1086/521264
Davies HD, McGeer A, Schwartz B, Green K, Cann D, Simor AE, Low DE: Invasive group A streptococcal infections in Ontario, Canada. Ontario Group A Streptococcal Study Group. N Engl J Med 1996,335(8):547–554. 10.1056/NEJM199608223350803
Hollm-Delgado MG, Allard R, Pilon PA: Invasive group A streptococcal infections, clinical manifestations and their predictors, Montreal, 1995–2001. Emerg Infect Dis 2005,11(1):77–82.
Thigpen MC, Richards CL Jr, Lynfield R, Barrett NL, Harrison LH, Arnold KE, Reingold A, Bennett NM, Craig AS, Gershman K, et al.: Invasive group A streptococcal infection in older adults in long-term care facilities and the community, United States, 1998–2003. Emerg Infect Dis 2007,13(12):1852–1859.
Kotloff KL, Corretti M, Palmer K, Campbell JD, Reddish MA, Hu MC, Wasserman SS, Dale JB: Safety and immunogenicity of a recombinant multivalent group a streptococcal vaccine in healthy adults: phase 1 trial. Jama 2004,292(6):709–715. 10.1001/jama.292.6.709
McNeil SA, Halperin SA, Langley JM, Smith B, Warren A, Sharratt GP, Baxendale DM, Reddish MA, Hu MC, Stroop SD, et al.: Safety and immunogenicity of 26-valent group a streptococcus vaccine in healthy adult volunteers. Clin Infect Dis 2005,41(8):1114–1122. 10.1086/444458
Shulman ST, Tanz RR, Kabat W, Kabat K, Cederlund E, Patel D, Li Z, Sakota V, Dale JB, Beall B: Group A streptococcal pharyngitis serotype surveillance in North America, 2000–2002. Clin Infect Dis 2004,39(3):325–332. 10.1086/421949
Shulman ST, Tanz RR, Dale JB, Beall B, Kabat W, Kabat K, Cederlund E, Patel D, Rippe J, Li Z, et al.: Seven-year surveillance of north american pediatric group a streptococcal pharyngitis isolates. Clin Infect Dis 2009,49(1):78–84. 10.1086/599344
Gust DA, Darling N, Kennedy A, Schwartz B: Parents with doubts about vaccines: which vaccines and reasons why. Pediatrics 2008,122(4):718–725. 10.1542/peds.2007-0538
Allred NJ, Shaw KM, Santibanez TA, Rickert DL, Santoli JM: Parental vaccine safety concerns: results from the National Immunization Survey, 2001–2002. Am J Prev Med 2005,28(2):221–224. 10.1016/j.amepre.2004.10.014
Kennedy AM, Brown CJ, Gust DA: Vaccine beliefs of parents who oppose compulsory vaccination. Public Health Rep 2005,120(3):252–258.
Bardenheier B, Yusuf H, Schwartz B, Gust D, Barker L, Rodewald L: Are parental vaccine safety concerns associated with receipt of measles-mumps-rubella, diphtheria and tetanus toxoids with acellular pertussis, or hepatitis B vaccines by children? Arch Pediatr Adolesc Med 2004,158(6):569–575. 10.1001/archpedi.158.6.569
Liu JT, Hammitt JK, Wang JD, Liu JL: Mother's willingness to pay for her own and her child's health: a contingent valuation study in Taiwan. Health Econ 2000,9(4):319–326. 10.1002/1099-1050(200006)9:4<319::AID-HEC521>3.0.CO;2-3
Arana JE, Leon CJ: Willingness to pay for health risk reduction in the context of altruism. Health Econ 2002,11(7):623–635. 10.1002/hec.687
Zikmund-Fisher BJ, Sarr B, Fagerlin A, Ubel PA: A matter of perspective: choosing for others differs from choosing for yourself in making treatment decisions. J Gen Intern Med 2006,21(6):618–622. 10.1111/j.1525-1497.2006.00410.x
Zhou F, Santoli J, Messonnier ML, Yusuf HR, Shefer A, Chu SY, Rodewald L, Harpaz R: Economic evaluation of the 7-vaccine routine childhood immunization schedule in the United States, 2001. Arch Pediatr Adolesc Med 2005,159(12):1136–1144. 10.1001/archpedi.159.12.1136
Prosser LA, Ray GT, O'Brien M, Kleinman K, Santoli J, Lieu TA: Preferences and willingness to pay for health states prevented by pneumococcal conjugate vaccine. Pediatrics 2004,113(2):283–290. 10.1542/peds.113.2.283
Lee GM, Salomon JA, LeBaron CW, Lieu TA: Health-state valuations for pertussis: methods for valuing short-term health states. Health Qual Life Outcomes 2005, 3: 17. 10.1186/1477-7525-3-17
Bala MV, Wood LL, Zarkin GA, Norton EC, Gafni A, O'Brien BJ: Are health states "timeless"? The case of the standard gamble method. J Clin Epidemiol 1999,52(11):1047–1053. 10.1016/S0895-4356(99)00074-8
Dolan P, Stalmeier P: The validity of time trade-off values in calculating QALYs: constant proportional time trade-off versus the proportional heuristic. J Health Econ 2003,22(3):445–458. 10.1016/S0167-6296(02)00120-0
Drummond MF, O'Brien B, Stoddart GL, Torrance GW: Methods for the Economic Evaluation of Health Care Programmes. 2nd edition. Oxford, UK: Oxford University Press; 1997.
Meyerhoff AS, Weniger BG, Jacobs RJ: Economic value to parents of reducing the pain and emotional distress of childhood vaccine injections. Pediatr Infect Dis J 2001,20(11 Suppl):S57–62.
King JT Jr, Tsevat J, Lave JR, Roberts MS: Willingness to pay for a quality-adjusted life year: implications for societal health care resource allocation. Med Decis Making 2005,25(6):667–677. 10.1177/0272989X05282640
Corso PS, Hammitt JK, Graham JD, Dicker RC, Goldie SJ: Assessing preferences for prevention versus treatment using willingness to pay. Med Decis Making 2002,22(5 Suppl):S92–101. 10.1177/027298902237713
Ortega-Sanchez IR, Lee GM, Jacobs RJ, Prosser LA, Molinari NA, Zhang X, Baine WB, McCauley MM, Miller T: Projected cost-effectiveness of new vaccines for adolescents in the United States. Pediatrics 2008,121(Suppl 1):S63–78. 10.1542/peds.2007-1115H
Feeney A, Handley SJ: Comparisons, mental models, and the action effect in judgments of regret. Mem Cognit 2006,34(7):1422–1430.
Gilovich T, Medvec VH: The experience of regret: what, when, and why. Psychol Rev 1995,102(2):379–395. 10.1037/0033-295X.102.2.379
Leach FR, Plaks JE: Regret for errors of commission and omission in the distant term versus near term: the role of level of abstraction. Pers Soc Psychol Bull 2009,35(2):221–229. 10.1177/0146167208327001
Baron J: Judgment misguided: Intuition and error in public decision making. New York: Oxford University Press; 1998.
Fredrickson DD, Davis TC, Arnould CL, Kennen EM, Hurniston SG, Cross JT, Bocchini JA Jr: Childhood immunization refusal: provider and parent perceptions. Fam Med 2004,36(6):431–439.
Gold MSJE, Russell LB, Weinstein MC: Cost-effectiveness in Health and Medicine. New York: Oxford University Press; 1996.
Lubetkin EI, Jia H, Franks P, Gold MR: Relationship among sociodemographic factors, clinical conditions, and health-related quality of life: examining the EQ-5D in the U.S. general population. Qual Life Res 2005,14(10):2187–2196. 10.1007/s11136-005-8028-5
Frew EJ, Whynes DK, Wolstenholme JL: Eliciting willingness to pay: comparing closed-ended with open-ended and payment scale formats. Med Decis Making 2003,23(2):150–159. 10.1177/0272989X03251245
Smith RD: Sensitivity to scale in contingent valuation: the importance of the budget constraint. J Health Econ 2005,24(3):515–529. 10.1016/j.jhealeco.2004.08.002
Yeung RY, Smith RD: Can we use contingent valuation to assess the demand for childhood immunisation in developing countries?: a systematic review of the literature. Appl Health Econ Health Policy 2005,4(3):165–173. 10.2165/00148365-200504030-00005
We thank the physicians at the Harvard Vanguard Medical Associates Kenmore and Braintree practice sites for their assistance with this study. We also acknowledge the contribution to this work by Elizabeth Pfoh and Pamela Butler in the Department of Population Medicine.
Funding/Support: This study was supported by the Agency for Healthcare Research and Quality, US Department of Health and Human Services Grant, 5 K08 HS013908-04 (to GML).
Financial Disclosures: None.
The authors declare that they have no competing interests.
GL participated in the conception and design, acquisition of data, analysis and interpretation of data, drafting of the manuscript, statistical analysis, and the obtaining of funding. JS participated in the conception and design, analysis and interpretation of data, statistical analysis, and critical revision of the manuscript. CG participated in the acquisition of data, administrative, technical, and material support, and critical revision of the manuscript. JH participated in the conception and design, analysis and interpretation of data, and critical revision of the manuscript. All authors read and approved the final manuscript.
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Lee, G.M., Salomon, J.A., Gay, C. et al. Preferences for health outcomes associated with Group A Streptococcal disease and vaccination. Health Qual Life Outcomes 8, 28 (2010). https://doi.org/10.1186/1477-7525-8-28
- Septic Arthritis
- Local Reaction
- Necrotizing Fasciitis
- Toxic Shock Syndrome