WILLINGNESS TO PAY FOR HYPOTHETICAL MALARIA VACCINES IN THE GAMBIA

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(1)TAIPEI MEDICAL UNIVERSITY. SCHOOL OF HEALTH CARE ADMINISTRATION MASTER‟S THESIS. WILLINGNESS TO PAY FOR HYPOTHETICAL MALARIA VACCINES IN THE GAMBIA. AWA BADJAN. ADVISOR: CHAO-HSIUN TANG, PHD. DATE: JUNE 2011.

(2) Taipei Medical University Master‟s Thesis School of Health Care Administration. Willingness to pay for Hypothetical Malaria Vaccines in The Gambia. Awa Badjan. June 2011.

(3) Taipei Medical University. School of Health Care Administration. Master‟s Thesis. Willingness to pay for Hypothetical Malaria Vaccines in The Gambia. AWA BADJAN. Advisor: Chao-Hsiun Tang, PhD. Date: June 201.

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(7) Acknowledgement I would like to express my sincere gratefulness to my advisor, Professor Chao-Hsiun Tang for her patience, kindness, encouragement and good listening. I am grateful to her unlimited guidance and continuous support throughout the project and without her help, this thesis would not be completed. My grateful thanks also extended to my co-advisor, Dr Bojang of medical research council for his valuable help and guidance.. I am also deeply grateful to my parents, Edrissa Badjan and Fatou Drammeh who are continuous encouraging and supporting me. I will never forget their continuous praying and “Duaa”. I also thank my sisters and brothers for being there for me during this process.. My sincere thanks also goes to my husband, Musa E.A. Kijera for his continuous support, help and encouraging me to do my master without his often help this work cannot be done. I will not also forget my sweet daughter, Nyima Isatou Kijera for her patience and continuous waiting to finish this study. Finally, I wish to express my thanks to all the assistant of my professor especially Titan and Poya for their continuous support.. Title of Thesis: “Willingness to Pay for Hypothetical Malaria Vaccines in The Gambia” Author: Awa Badjan, MBA Thesis advised by: Chao-Hsiun Tang, Ph.D. I.

(8) ABSTRACT AIMS: This study aims to set priorities for anti disease Malaria Vaccines by determining the household Head and already diagnosed Malaria patients their preferences for the Vaccine METHODS: A bidding game technique was used to elucidate Willingness to pay in The Gambia and one hundred Household heads and one hundred already diagnosed Malaria patients were interviewed. RESULTS: People that are highly educated are more willing to pay than those who are less. House hold heads around 30s were more willing to pay than those in their 40s. Monogamy household heads were also willing to pay than polygamy household heads. Those that stay in the area less than 20 years were willing to pay more than those that spend their entire life in a particular place. Those that earn more were willing to pay more than those that earn less. CONCLUSIONS: While Malaria continues to be a problem, it is likely that anti disease Malaria vaccine will become available in the foreseeable future, lessons from the past suggests that lack of acceptance and support from the intended recipients may lead to less than optimal compliance, and hence efficacy. For the planning of Vaccine development and application strategies, it is therefore, highly important to take community views into account. Here it is argued that such information could help researchers and funding agencies to set priorities for future vaccine research.. II.

(9) TABLE OF CONTENTS Table of Content. Page. Acknowledgements…………………………………………………………………….. I. Abstracts……………………………………………………………………………….. II. Table of Content……………………………………………………………………….... III. List of Tables…………………………………………………………………………… VI List of Figures…………………………………………………………………………... VII Chapter 1: Introduction………………………………………………………………. 1. 1.1 Epidemiology of Malaria…………………………………………............. 1. 1.2 Cost of Illness of Malaria…………………………………………………. 7. 1.3 Current Preventive Strategies…………………………………………….. 15 1.4 Problem Statements………………………………………………………. 22 1.5 Objective Statements……………………………………………………... 23. 1.6 Significant of the Study…………………………………………………... 24. Chapter 2: Literature Review………………………………………………………… 25 2.1 Methodology of Willingness to Pay Approach…………………................ 25. III.

(10) 2.2 Studies Using Contingent Valuation Method to Value Cost of Illness of Malaria………………………………………………….…………………….. 34. 2.3 Studies Using Contingent Valuation Method to Value Cost of Illness of Other Diseases…………..................................................................................... 35 Chapter 3: Methodology………………………………………………………………. 39. 3.1 Conceptual Framework…………………………….……………………... 39. 3.2 Hypotheses……………………………………………………………….. 41 3.3 Operational definitions of study variables………………………………... 42 3.4 Study Designs and Subjects………………………………………………. 47. 3.5 Study Site…………………………………………………………………. 51. 3.6 Willingness to pay………………………………………………………... 52 Chapter 4: Results……………………………………………………………………... 61. 4.1 Descriptive Statistics of Continuous and Categorical Variables …………... 61. 4.2 Bivariate Analysis of Socio Demographic Variables……………………... 57. 4.3 Bivariate Analysis of Socio Economic Status variables………………….. 60 4.4 Linear Regression Analysis of Socio Demographic Variables…………… 65 4.5 Linear Regression Analysis of Socio Economic Status Variables………... 68. IV.

(11) Chapter 5: Discussion…………………………………………………………………. 76 5.1 Discussion ………………………………………………………………... 76. 5.2 Conclusion Recommendation…………………………………………….. 83. References………………………………………………………………………………. 84. Appendixes……………………………………………………………………………... 90 Appendix 1: Ethics committee letter……………………………………………………. 90 Appendix 2: Figures…………………………………………………………………….. 91. Appendix 3: Formal Questionnaire…………………………………………………….. 93. V.

(12) LIST OF TABLES Page Table 2.1. Studies using Willingness to Pay to Value other Diseases………... 37. Table 3.1. Operational definition of the dependent and independent variables. 46. Table 4.1. Descriptive Statistics of Continuous and Categorical Variables…... 55. Table 4.2. Bivariate Analysis of Socio Demographic Variables…………….... 58. Table 4.3. Bivariate Analysis of Socio Economic Status variables…………... 62. Table 4.4. Linear Regression Analysis of Socio Demographic Variables……. 67. Table 4.5. Linear Regression Analysis of Socio Economic Status Variables.... 70. Table 4.6. Regression Analysis of Simple and Multiple Regressions………... 74. VI.

(13) LIST OF FIGURES Page Figure 1. Malaria Risk, 1946, 1965, 1994……………... VII. 21.

(14) CHAPTER ONE. INTRODUCTION. 1.1 EPIDEMIOLOGY OF MALARIA Scientists and politicians have been interested in malaria control for many years and numerous programmes have been implemented to fight this infectious disease, which causes 300-500 million clinical cases and kills an estimated 1 million people annually in Africa alone (Sauerborn et al. 2005). A significant and sustainable reduction in the global malaria burden has not been achieved and according to some malaria vaccine researchers, will remain out of reach unless an effective vaccine becomes available.. It may be difficult to achieve a sustainable malaria control given the parasite‟s ability to evade the host immune responses; an effective vaccine eliciting lifelong protection would be most desirable.. Plasmodium falciparum, the most deadly, human malaria parasite, is a master of antigenic variation. The morbidity and mortality associated with falciparum malaria is in large part due to the ability of infected erythrocytes to sequester in the deep vascular bed of inner organs, such as the brain and placenta, resulting in a broad spectrum of clinical disease manifestations including localized hypoxia, inflammatory reactions and the syndromes of cerebral and maternal malaria.. Malaria is therefore a massive problem, which plagues all segments of the society. The effect of malaria on people of all ages is quite immense. It is however very serious among pregnant women and children because they have less immunity. When malaria infection is not properly treated in pregnant women, it can cause anemia and also lead to miscarriages, stillbirths, underweight babies and maternal -1-.

(15) deaths. Also, frequent cerebral malaria can lead to disabling neurological sequelae. Furthermore, malaria in school children is a major cause of absenteeism in endemic countries. It is estimated that about 2% of children who recover from cerebral malaria suffer brain damage including epilepsy (WHO/UNICEF, 2003).Hence, among young children frequent episodes of severe malaria may negatively impact on their learning abilities and educational attainment. This is a threat to human capital accumulation, which constitutes a key factor in economic development. The debilitating effects of malaria on adult‟s victims are very much disturbing. In addition to time and money spent on preventing and treating malaria, it causes considerable pain and weakness among its victims. This can reduce peoples working abilities. The adverse impacts of the disease on household production and gross domestic products can be substantial. Malaria therefore is not only a public health problem but also a developmental problem. At the national level, apart from the negative effect of loss productivity on the major sectors of the economy, malaria has negative effects on the growth of tourism, investments and trade especially in endemic regions.. Malaria presents a major socio- economic challenge to African countries since it is the region most affected. This challenge cannot be allowed to go unnoticed since good health is not only a basic human need but also a fundamental human rights and a prerequisite for economic growth (Streeten, 1981).. Many African families spend a quarter of their annual income on malaria treatment. At national level, malaria control and treatment can cut aggregate growth by about 1.3% per year (World Malaria Report, 2005).. -2-.

(16) WHAT IS MALARIA Malaria is an infectious disease caused by a parasite, Plasmodium, which infects red blood cells. Malaria is characterized by cycles of chills, fever, pains and sweating. Historical records suggest Malaria has infected humans since the beginning of Mankind. The name “mal aria” (meaning “bad air” in Italian) was first used in English in 1740 by Walpole when describing the disease. The term was shortening to “Malaria” in the 20th century. Laveran in 1880 was the first to identify the parasites in human blood. In 1889, R Ross discovered that mosquitoes transmitted malaria. Of the four common species that causes malaria, the most serious type is Plasmodium. Falciparum Malaria. It can be life threatening. However, another relatively new species Plasmodium Knowles, is also a dangerous species that is typically found only in long-tailed and pigtail Macaque Monkeys. Like P. Falciparum, P. Knowles may be deadly to any one infected. The other three common species of malaria (P.vivax, P.Malariae and P.ovale) are generally less serious and are usually not life threatening. It is possible to be infected with more than one species of plasmodium at the same time. Fever is the main symptoms of Malaria. The most severe Manifestations are cerebral malaria (Mainly in children and persons without previous immunity), anemia (Mainly in children and pregnant woman), and kidney and other dysfunction (e. g respiratory distress syndrome).Persons repeatedly exposed to the diseased acquired a considerable degree of clinically immunity, which is unstable and disappears after a year away from the endemic-disease environment. Immunity reappears after malarial bouts if the person returns to an endemic-disease zone. Most likely to die of malaria are persons without previous immunity, primarily children or persons from parts of the same country (e.g. High altitudes) where transmission is absent, or persons from more industrialized countries where the disease does not exist (Thomas C. Nchinda 1998).. -3-.

(17) EPIDEMIOLOGY In the Gambia, malaria is one of the leading causes of morbidity and mortality, especially among children under 5 years. However, during the past four years, there has been a 74% reduction in the number of admissions in selected facilities in the country (Ceesay et al. 2008). Although the economic burden of malaria has not been fully determined, there is no doubt that the disease accounts for considerable loss of days of productivity among the adult population, absenteeism from schools and workplaces and increased household expenditure on health. Malaria is therefore not only a health problem but also a developmental one. The linkage between malaria and poverty is well recognized.. In children with malaria, the parasite, mosquito borne disease, typically develop fever, vomiting, headache and flu like symptoms. When untreated, malaria can progress rapidly to convulsions, coma and death. Children who survive an episode of severe malaria can suffer from learning impairments and brain damage. Anaemia, lethargy and poor childhood development can lead to repeated episode of malaria (World Malaria Report, 2005).. Malaria is highly seasonal in The Gambia. Transmission during the rainy season (June – October) is intense with 80% of severe cases occurring in October and November. Plasmodium falciparum is the dominant parasite. The highest rates are recorded in rural areas.. According to Department of State for Health in 2004, it is the leading cause of morbidity and mortality, especially among pregnant women and children under 5 years.. Socio-economic determinants associated with childhood malaria have been identified as poor quality housing, low level of malaria prevention behaviors, shortage of effective drugs at the first point of. -4-.

(18) contact (the Village Health Service), poverty, limited number of drug stores and pharmacies and overreliance on traditional treatment (Koram, 1995).. The results of the Multiple Indicator Cluster Survey (MICS 2006) presents a 7% decrease in under-five mortality rates (from 141/1000 in 2000 to 131/1000). In addition to the MICS, reports from other studies also indicated that the program shows evidence of impact based on scientific studies performed over a seven-year period; ending in 2007. The investigations were based on data collected from three selected health facilities in the Western Health Region. The proportion of deaths attributed to malaria in two of those health facilities declined by 100% and 90%. The decline is associated with significant increases in coverage of key malaria interventions – IPT, and Insecticide-Treated Mosquito Nets (ITN) for children under five years and pregnant women. The 2006 MICS showed an increase use of ITNs from 14.5% in 2000 to 49% in 2006 by children less than five years of age. The data also show a 43% reduction between 2000 and 2006 in episodes of fever among children less than five years. This is strongly suggesting a reduced malaria incidence in the area.. Malaria mortality and morbidity have been observed to slow economic growth by reducing capacity and efficiency of the labor force. This is from a macroeconomic perspective. Basic economic theory postulates that the quantity of a given output that is produced is a function of several factors including the capital stock, labor force and the quality of labor available. Based on this, it could be argued that the effects of malaria on labor diminishes total output and for that matter national income. Asante and Okyere confirmed that a 10% reduction in malaria was associated with 0.3% higher growth in the economy. In a cross country econometric estimation of the effects of malaria on national income by Gallup and Sachs in 2001, concluded that countries with substantial level of malaria grew 1.3% less per person per year for the period 1965-1990.. -5-.

(19) In a similar study to explore the impact of macro policy variables on malaria morbidity across countries and the importance of indirect effects of malaria on total factor productivity, McCarthy and Wolf (2000) found a negative association between higher malaria morbidity and Gross Domestic Product (GDP) per capita growth rate. Most of the sub-Saharan African countries incurred an average annual growth reduction of 0.55%. Sachs and Malaney (2002) have also observed that where malaria prospers most, human society have prospered least.. There is an association between income levels and rate of incidence. High rate of poverty and low overall rate of GDP/capita rates often occurs in countries with high rate of malaria. Malaria can also impact a country‟s ability to compete in the global economy. Poor health can influence a country‟s economic growth and development (Sachs & Malaney, 2000).. The significant economic losses due to Malaria can cause as much as 1.3% of a country GDP where the transmission is really high. Over the long term, these aggregated annual losses have resulted in substantial differences in GDP between countries with and without malaria, particularly in Africa.. Over the 1965 to 1990 period, poor countries on average grew slower than rich countries, but poor countries also had lower initial human capital, followed less successful economic policies, and were disadvantaged geographically (Gallup & Sachs, 2001).The malaria index for 1965 is constructed similarly to the malaria index for 1994.It is the product of the fraction of the population living in areas with high malaria risk in 1965 times the fraction of malaria cases in 1990 that the P. falciparum. This assumes that the relative shares of P. falciparum cases did not change substantially from 1965-1990.. -6-.

(20) 1.2 COST OF ILLNESS OF MALARIA Malaria attack results in morbidity, disability and in some cases mortality. The effects of these conditions constitute the cost of illness. Andreano and Helminiak (1988) put the effects of tropical disease into perspective by providing a typology of disease effects. They classified the economic and social impacts of tropical diseases into four as: (1) Health consumption effects, (2) Social interaction and leisure effects, (3) Short term production effects, (4) Long term production and consumption effects.. These effects result in various cost components, which can be categorized into direct costs, indirect costs and intangible costs (Shepard et al., 1991). These costs may be borne by an individual, the household, the health care provider and/or the economy in various forms (Malaney, 2003).. -7-.

(21) Direct Cost The exposure of people of the bites of the Anopheles Mosquito results in sickness and if not promptly and efficiently addressed may result in the death of the victim. The process of seeking treatment involves cost to the individual and his household. The fear of contracting malaria also urges people to protect themselves. The theory of averting behaviors predicts that a person will continue to take protective actions as long as the perceived benefits exceed the costs of doing so. Since these processes involve the expense of tangible resources, the resource cost is termed direct cost to the individual and his household in the form of treatment and preventive costs.. In addition, it is the duty of every government to promote and sustain a healthy lifestyle for its people. The government ensures that resources are provided to maintained and operate a good health system. This resource cost constitutes the non private medical cost (social cost) to the institution and the society in general if the services are subsided for consumers.. The direct cost of illness to the household (private cost) could be obtained with less controversy since it is an ex-post exercise which could be obtained through recalls. This is however not simple when it comes to the direct costs of a particular disease to the health system. Due to the nature of the health system, certain costs are shared by several activities which make the estimation of the institutional cost of a particular disease difficult. The health system provides general treatment and therefore malariarelated expenditures are often not separated from other health service costs in budgeting and accounting systems.. The best approach to the estimation of the institutional cost is to document precisely the inputs required to treat or prevent the disease but this is not only sophisticated but also laborious. According to Drummond et al. (1987), the shared costs could be prorated among various services by observing -8-.

(22) the total costs and opportunity them using hospital morbidity data. For personal costs, Cheese and Parker (1994) suggested that, the proportion of time spent by staff devoted to the case (disease) of interest could be observed and measured for the proportional calculation of the cost to the disease.. The cost of illness to the economy also includes tax exemptions on imported anti-malarial products. The direct costs may also include the resources that are spent directly or indirectly by various institutions like local governments, Non- Governmental Organizations (NGOs) and communities.. -9-.

(23) Indirect Cost During the period of the sickness, the individual may stop work completely of may work partially due to the debility associated with the disease on temporary bases. Situations like these may affect household production adversely. In certain cases, a household member will have to cut down his / her own duty to cater for the sick or perform the duties of the sick person. The subsequent decline in output in this case is termed indirect cost. These indirect costs mainly represent loss of potential productivity. This is not an out of pocket payment but the opportunity cost of both market and non market (unpaid domestic) productive time lost to the household.. The indirect cost of illness is often estimated through the human capital approach. The human capital approach considers the value of lost productivity as a result of illness and premature mortality. This perspective is based on the application of “neo-classical” market oriented economic principles. The human capital approach is therefore applied within the opportunity cost framework, which is central concept in market economics (Harwood, 1994).. The value of this lost is assumed to be equal to the earnings people could have earned but for the illness. The human capital approach applies forgone wages to estimate lost productivity. The opportunity cost of time could be evaluated as the marginal cost of labor. Brandt (1980) suggested that in subsistence agriculture with easily available land, labor is by far the most important input variable to production. This is because the marginal cost of labor (MCL) could be approximately by the marginal product of labor (MPL).. In a perfect market economy, the marginal product of labor is equal to the workers earning per day on the particular job at which he /she is working. This is however, not likely to be so due to the imperfections in the market especially in the economics of developing countries. Various proxies are - 10 -.

(24) often used to value the marginal product of labor for this reason. According to Mills (1989) the method that have been used to appraise the lost productive time are varied and include average agricultural wage, salaries, marginal productivity calculated from a Cobb-Douglas production function, income per capita, legislated minimum wage among others. However, Prescott (1999) is with the view that some of these methods may poorly represent the actual marginal product of labor and therefore must be used with caution.. It is possible that mosquito infested areas could have experience reduced land utilization since people would not want to invest in such malarious areas. This could have a negative effect on the development of that area as a result a decline in tourism, agriculture and industrial activities among other things. This constitutes indirect costs to the local economy and the nation as a whole.. Travel times to seek treatment or buy drugs are important indirect cost components in the area where people travel long distances to health facilities and drug stores. Another important indirect cost is waiting time at the health facility.. - 11 -.

(25) Mortality Cost Another important indirect cost of malaria is attributed to the permanent loss of labor days due to mortality. Thus, the death of the victim denies society of the benefits that would have been gained from the victim‟s productivity present of in the future. The premise for the estimation of this cost is that mortality destroys potential output. This potential loss of productivity is usually valued using market wage rate and the earnings in the future are discounted at a constant rate.. According to Hodgson and Meiners (1992) premature death represents a loss of economic product, equal to the discounted stream of earnings that otherwise would have been earned over the remaining expected life. The problem with this approach however is that, the life of non income producing older people, children and the unemployed is valued as negligible or zero. In situations like this, a disease like malaria, which has higher child mortality rate, will seem to present a lower disease burden on the society.. The idea of placing a monetary value on life has received its fair share of criticisms in the literature since it has been challenged on several grounds including ethical and methodological. For instance, people‟s earnings may not always accurately reflect their ability to produce due to market imperfections. Another concern also is how to value the death of those who are outside the labor force (e.g. children and the unemployed). Though it is methodolologically possible to value life in monetary terms by age groups and sex by assigning different weights, it is not clear if the life of all the people in a particular age cohort of sex group should be treated equally.. Notwithstanding these concerns, it has been argued that it is still necessary to place some value (not necessarily in monetary terms) on human life in economic cost estimation since failure to do so will set the value of life at zero. The number of years of life lost due to premature mortality could be - 12 -.

(26) enumerated without placing a monetary value on those years. This could be expressed as years of potential life lost (YPLL) (Single, 2001). The YPLL gives more emphasis to deaths among young members of the population as the death at a young age makes a high contribution to YPLL than a death at an older age.. - 13 -.

(27) Intangible Cost The final cost component is the intangible cost, which is explained by the health consumption and social interaction as well as the leisure effects of the disease. Malaria infection diminishes and or shortened the enjoyment (in economic terms) of good health. This is in the form of pain, suffering, anxiety and grief associated with the death of a family member. It also includes the loss of leisure time due to illness and the cost of not participating in social activities.. Though the intangible cost associated with a disease could be very substantial, the human capital approach fails to capture the costs of pain, suffering and the psychosocial consequence of illness and premature mortality (Mills, 1992). This has been a major limitation of the approach but Glenn et al. (1996) argues that this argument is flawed because intangibles such as pain, suffering, anxiety are strictly not costs in economic sense. This is because, economic costs are resources forgone in alternative uses but since psychological effects do not have resource consequences per se, they should be treated as negative benefits.. In addition, there is cost to households, which modify their social and economic decisions in response to risks of contracting malaria. For instance, high malaria prevalence in an area may compel households to cultivate crops that require less labor or may migrate to less malarious regions which may result in net output losses. This is what is termed as the risk-related behavior modification.. - 14 -.

(28) 1.3 CURRENT PREVENTIVE STRATEGIES Different types of Malaria Control Tool The treatment of malaria was severely compromised by increasing resistance of P.falciparum to chloroquine. Therapeutic efficacy testing of chloroquine conducted in Basse, Mansakonko (1998) and Farafenni (2001) showed clinical failure rate of 4%, 14% and 19% respectively. In 2003, in Brikama Health Centre, Chloroquine resistance was 28%. High levels of therapeutic failures to chloroquine, and significant increases in cases of severe anaemia (Bojang et al, 2005), have prompted a change in the first line drug for uncomplicated malaria. In 2004 the first-line drug for treatment of uncomplicated malaria was changed to combination treatment using S/P with CQ and in February 2008 a change to the more effective Artemisinin-based Combination Therapy (ACT) was implemented.. Malaria Vaccine Vaccines are often the most cost effective tools for public health. With over one million deaths annually attributed to malaria, an effective vaccine is an urgently needed intervention. The two intended vaccines are: (I) The vaccine against maternal malaria; and (II) The Vaccine against childhood malaria.. - 15 -.

(29) Insecticide Treated Nets (ITNs) The growing body of evidence suggests that insecticides treated nets (ITNs) substantially reduce the frequency and severity of clinical episodes of Malaria .Research shows that ITNs could save 500,000 African children a year at a very low cost. (Onwujekwe et al., 2001). Obinna Onwujekwe has shows that most studies documented a reduction of 20%-63% in malaria rates after the introduction of ITNs.. The national targets are to increase the utilization of ITNs by 80% of the target population by December 2015. According to MICS III survey report, the national ITN usage for the 0 – 59 months was 49%. However, this survey did not cover ITN usage for pregnant women. The MIS 2007 conducted in the Western Health Region, showed that the percentage of pregnant women who slept under a mosquito net was 86.8%.. It is pointed out that research carried out in Dakar demonstrated the efficacy of insecticide treated nets for reducing infant‟s deaths and subsequent large scale multicentre studies in six countries across Africa confirmed this finding (Nchinda, 1998). However, costs of the nets and treatment still inhibit wide scale use. Ongoing research seeks ways of reducing these costs, such as social marketing, possible involvement of the private sector, cost effective methods for net treatment, the most appropriate nets and proper procurement and insecticides and treatment of the nets.. - 16 -.

(30) Indoor Residual Spraying (IRS) Spraying houses with insecticides (Indoor Residual Spraying, IRS) to kill mosquitoes is one of the main methods that have been used to control Malaria on a large scale.IRS has helped to eliminate from great parts of Asia, Russia, Europe and Latin America and successful IRS programmes have also been run in parts of Africa (Pluess et al., 2010).. Mosquito Repellent Cream (DEET) Mosquito repellent containing diethyl toluamide (DEET) is recommended as the most effective form of bite-preventive treatment. It has an excellent safety profile in adults, children and pregnant woman and has been used in over 8 million doses in the last 50 years.. However, there are people who dislike DEET and for them there are other products such as non-DEET jungle Formual, Bayrepel or Mosiguard (made from eucalyptus oil).. Insects repellent containing over 30 to 50 per cent DEET will effectively repel mosquitoes when applied to exposed skin .Other products are less effective but may have some use. Lemon scent was found to protect citrus groves from Mosquitoes and refined lemon eucalyptus oil on skin also repels mosquitoes.. - 17 -.

(31) Case Management in The Gambia The Gambia is making significant progress towards the 2010 targets in terms of coverage and impact on malaria morbidity and mortality. Since the commencement of Global Fund Aids, Tuberculosis and Malaria (GFATM) in 2004, coverage of target populations with malaria interventions have increased substantially in the Western Health Region under the Round 3 project. The remaining five regions are being covered under the Round 6 project.. Significant efforts have been made to ensure early diagnosis and prompt treatment through improved access to effective anti-malarial drugs. The quality of care in public and private health facilities have improved. The capacity of health facilities and community-based malaria control activities were strengthened, in order to reduce the malaria burden.. According to the Malaria Indicator Survey (MIS), coverage in prompt treatment from the Western Health Region showed that 22.1% of children under-five had a fever in the two weeks preceding the survey. Of these, 65.5% took anti-malarial drugs, 13.1% took the drug within 24 hours of the on-set of the symptoms.. Malaria case management remains a critical component of the malaria control strategies. This however requires early diagnosis and prompt treatment with effective medicines. Effective and affordable drugs available to treat malaria in developing countries are still limited especially following the development of resistance against chloroquine and sulfadoxine-pyrimethamine. Improvement has been achieved with the increasing development of artemisinin based combination therapies (European and Developing Countries Clinical Trials Partnership 2010).. - 18 -.

(32) Malaria in Pregnancy (MIP) Malaria in pregnancy services have been expanded to both public and private health facilities coupled with community sensitization and mobilization resulted to increased uptake of IPTp2 from 33% to 46.6% (MICS III). In addition, ITN usage has significantly increased to 86.8% (MIS II) and 83% (MIS I) for Western Health region and the other regions respectively. There were no instances of antimalarial drugs stock-outs reported in the country.. In pregnant woman during their first month of life, Malaria is recognized as a risk factor for low birth weight and probably decreases the survival of offspring.. Willingness to pay is a tool use to measure disease burden. It is widely use by economist and other researchers around the world. This technique is use in Most of the African countries like Ghana, Burkinafaso, Tanzania etc. However, the method has not been use in The Gambia.. Therefore the objective of this study is to help researchers, funding agencies and policy makers to set priorities for malaria vaccine research that protect pregnant women from the pathology of maternal malaria and also the vaccine to protect infants from severe childhood malaria from the population for which they are intended.. Results of this study increase our knowledge of economic impact on the people and also guide us about people preference because if the populace is not supportive to any intervention, that intervention will not work or survive. So therefore it is very important to consider the human fact especially in an intended population. A study done in Burkina Faso in 2005 revels that the current problems of polio eradication in Nigeria shows that even the best intended disease prevention measures fail if the. - 19 -.

(33) populace is not supportive. The same may happen with novel intervention strategies against malaria, if the preferences of the population for which they are intended are not taken into account. Also an economic evaluation of Malaria vaccine would provide important information to health care policy decision makers and private payers about the vaccine economic values.. - 20 -.

(34) Data Source: Gallup and Sachs (2001) Figure 1: Malaria Risk, 1946, 1965, 1994 - 21 -.

(35) 1.4 PROBLEM STATEMENTS The malaria burden is a challenge to human development. It is both a cause and consequence of under development. Therefore it is a serious disease in Africa which causes major threats to development. It is the leading cause of mortality in children under five years, a significant cause of adult morbidity and the leading cause of workdays lost due to illness.. Despite its devastating effects, the importance of a malaria free environment in promoting economic development and poverty reduction has not been fully appreciated in The Gambia. The study is an attempt to provide this needed information.. - 22 -.

(36) 1.5 OBJECTIVE STATEMENTS The aims of the study are: (I). To assess diagnosed malaria patients their preferences in Willingness to pay for a hypothetical Malaria vaccines.. (II). To assess community preference in Willingness to Pay (WTP) for malaria vaccines.. - 23 -.

(37) 1.6 SIGNIFICANT OF THE STUDY RESULTS A recent upsurge of Malaria in endemic disease areas with explosive epidemics in many parts of Africa is probably caused by many factors, including rapidly spreading resistance to antimalarial drugs, climate changes, and population movements. In Africa, malaria is caused by plasmodium falciparum and is transmitted by Anopheles gambiae complex.. Therefore with this study, it should provide policy makers with Importance evidence on the monetary value placed on Malaria vaccines so that subsequent research projects can be carry on for a better understanding of the Pathogenesis, vector dynamics, and epidemiology and socio economic aspects of the disease. The study results will also help researchers and funding agencies to set priorities for further research.. An international collaborative approach is needed to build appropriate research in a national context and a solid research base both for developing antimalarial drugs and vaccines to effectively translate research results into practical applications in the field. Initiatives for malaria in Africa can combine malarial strategies to plan and coordinate partnerships, networking, and innovative approaches between African scientists and their northern partners. However, it will also help funding agencies and researchers to set priorities for further research projects.. - 24 -.

(38) CHAPTER TWO LITERATURE REVIEW 2.1 METHODOLOGY OF WILLINGNESS TO PAY APPROACHES Willing to pay (WTP) is a measure of value based on the premise, central to economic theory, that the value of a good is simply what it is worth to those who consume it or benefit from it. The amount an individual is willing to pay for a particular good may be higher or lower, than the cost of that good (Cunningham, K. 2010).. Willing To Pay is one of the two standard measures of economic value. It is the appropriate measure in the situation where an agent wants to acquire a good. Minimum Willingness to accept (WTA) compensation is the appropriate measure in a situation where an agent is being asked to voluntarily give up a good. Both of these measures are Hicksian consumer surplus measures and are often defined net of the price actually paid or received. Whether WTP or WTA is the correct measure depends upon the property right to the good. If the consumer does not currently have the environmental good and does not have a legal entitlement to it, the correct property right is WTP.. If the consumer has a legal entitlement to it and is being asked to give up that entitlement, the correct property right is WTA. For marketed goods, theoretically the difference between the two measures should generally be small and unimportant as long as income effects and transaction costs are not large. For non marketed goods, this may not be the case as the difference between WTP and WTA is also dependent upon the substitutability of the non-marketed good for goods available on the market (Carson, 1999).. - 25 -.

(39) The Cost of Illness (COI) approach employing the human capital augment is questioned on the grounds of whether production is an adequate or ethical measure of human value and whether earnings is an adequate measure of production. This is because people‟s earnings do not always accurately reflect their ability to produce. The willingness to pay (WTP) approach has therefore been advanced as an alternative to address some of these limitations. This approach considers the amount people are willing to pay to avoid or decrease their risk of injury, disease or death so as to keep alive and healthy. The WTP approach has the advantage of quantifying all costs of illness to society, including the intangibles (WHO 2001). An important issue that is addressed by the WTP approach is that it accounts for consumer behavior in purchasing goods and services.. The fundamental framework underpinning the WTP concept is the „value theory‟. An important assumption of the value theory is that consumers value their own consumption, e.g. good health and that they rationally seek to maximize the value of their consumption as best they can, subject to various constraints such as their income and price. It is expected that, rational people will be willing to pay to price that reflects the value they place on their health and life. The WTP therefore reflects individual preferences over health risks. It is known that individual preferences are unique and individual demands for risk reduction vary. This variation may depend on several factors including the level of risk, the type of risk and the socio-economic characteristics of the population including income differences. This means that income and circumstances could play a role in determining the size of willingness- to-pay estimates.. In making such a decision, people assess the pains and suffering associated with the particular condition. The values of lost productive and leisure time, among others and weigh them against the expected benefits. This means that if the approach is well implemented, it makes it possible to capture the direct and indirect costs associated with a particular issue. - 26 -.

(40) There are different ways of eliciting willing to pay approach. They are the open- ended questions, payment card questions, closed ended questions and the bidding game. Close ended questions includes the referendum questions and the dichotomous choice questions. The dichotomous choice formats have the advantage of closely mimics our day to day markets decisions and reduces the incentives for strategic behavior. Range bias is unavoidable in the payment card format while it is also belief that starting point bias is inevitable in the bidding game format. However, Economist belief that dichotomous choice is free of such biases.. In dichotomous choice questions, each respondent accepts or rejects only one price. By varying the price in different subsamples, the mean Willingness to pay can be estimated. In open ended questions, the Maximum Willingness to Pay is elicited from each respondent. As it is difficult to state the maximum Willingness to pay directly, a bidding game is often used where the bid is raised or lowered until the Maximum Willingness to pay is reached. A disadvantage of using a bidding game is that it often leads to problems of starting point bias (i.e., the maximum willingness to pay is affected by the first bid in the bidding game). On the other hand, the bidding game gives more information from each respondent than the dichotomous choice question approach.. Economists have developed a variety of techniques to value nonmarket amenities consistent with the valuation of marketed goods. These techniques are based upon either observed behavior (revealed preferences) towards some marketed good with a connection to the non-marketed good of interest or stated preferences in surveys with respect to the non-market good. The stated preference approach is frequently referred to as contingent Valuation especially when it is used in the context of environmental amenities. The use of contingent valuation (CV) has engendered a heated debated between proponents and critics (Carson, 1999). - 27 -.

(41) CONTINGENT VALUATION METHOD This is a survey- based method frequently used for placing monetary values on environmental goods and services not bought and sold in the market places. It is also known as the stated preference approach. Contingent Valuation (CV) Method is usually the only feasible method for including passive use considerations in an economic analysis, a practice that has engendered considerable controversy. The issue of what a CV study tries to value is first addressed from the perspective of a policy maker and then the controversy over the inclusion of passive use is taken up in more details. The major uses and positions taken in the technical debate over the use of CV are summarized from a user‟s perspective. Key design and implementation issues involved in undertaking a CV survey are examined and the reader is provided with a set of factors to examine in assessing the quality of a CV study.. A CV survey constructs scenarios that offer different possible future government actions. Survey respondents are then asked to state their preferences concerning those actions. The choices made by the survey respondents are then analyzed in a similar manner as the choices made by consumers in actual markets. In both cases, economic value is derived from choices observed either in an actual market or in the hypothetical market created in the survey.. Under the simplest and most commonly used CV question format, the respondent is offered a binary choice between two alternatives, one being the status quo policy, the other alternative policy having a cost greater than maintaining the status quo. The respondent is told that the government will impose the stated cost (e.g. increased taxes, higher prices associated with regulation, or user fees) if the non status quo alternative is provided. The key elements here are that the respondent provides a “favor/not favor” answer with respect to the alternative policy (versus the status quo), where what the alternative policy will provide , how it will be provided, and how much it will cost have been clearly specified. - 28 -.

(42) A Contingent Valuation Study stimulates missing markets by asking people hypothetical questions about their Willingness to Pay (WTP) for a community. The valuation is then conditioned on the good being obtainable only if WTP covers the costs of production, and on the respondent thus loosing the opportunity to consume other goods for an amount equal to their stated WTP. The method is theoretical valid (i.e. individual characteristics and other factors affects WTP according to what would be expected. It also has a convergent validity (i.e. It produces results similar to those of other valuation techniques or result that differs from those obtained by other methods in a predictable way.. A CV method has been applied in the valuation of a number of goods and services where competitive market price does not exist. Example of studies in Health care include WTP for enrolment in an asthma management program and for antenatal care and as well as for priority setting between two life saving health care programmes and hip operations. The WTP for risk reductions in various areas has been estimated.. A CV Survey can create an idealized market for a pure public good whereby respondents face a choice between two different quantities of the good. The usual example is the status quo level of the good versus an alternative level that will entail a specified cost increase. Any particular good can have both direct use and passive use values. The exact dividing line between direct and passive use is to some degree dependent upon knowledge of physical and biological lineages upon what activities of consumers are observed. For instance, while swimming in a lake obviously involves direct water contact, connecting the distant wetlands necessary to support a duke hunter may be difficult. Even in the quintessential example of lost passive use, harm from the Exxon Valdex spill to households outside Alaska, household news watching behavior was influenced by spill coverage (Carson, 1999).. - 29 -.

(43) The Contingent Valuation Method (CVM) is used to estimate economic values for all kinds of ecosystem and environmental services. The method has greatly flexibility, allowing valuation of a wider variety of non markets goods and services that are possible with any other non markets valuation technique. It can be used to estimate both use and non use values, and it is the most widely used method for estimating non use values. It is also the most controversial of the non market valuation methods.. The Contingent Valuation Method involves directly asking people, in a survey how much they would be willing to pay for specific environmental services. In some cases, people are ask for the amount of compensation they would be willing to accept to give up specific environmental services. It is called “contingent” valuation, because people are asked to state their willingness to pay, contingent on a specific hypothetical scenario and description of the environmental service.. The Contingent Valuation Method is referred to as a “stated preference” method, because it asks people to directly state their values, rather than inferring values from actual choices, as the “reveled preference” methods do. It circumvents the absence of markets for environmental goods by presenting consumers with hypothetical markets in which they have the opportunity to pay for the good in question. The hypothetical markets may be modeled after either a private goods market or a political market.. The fact that contingent valuation is based on what people say they would do, as opposed to what people are observed to do, and is the source of its greatest strengths and its greatest weaknesses. Contingent valuation is one of the only ways to assign dollar values to non use values of the environment values that do not involved markets purchases and may not involved direct participation. These values are sometimes referred to as “passive use” values. They include everything from the - 30 -.

(44) basic life support functions associated with ecosystem health or biodiversity, to the enjoyment of a scenic vista or a wilderness experience, to appreciating the option to fish or bird watch in the future, or the right to bequest those options to your grandchildren. It also includes the value people place on simply knowing that giant pandas or whales exist.. It is clear that people value non use, or passive use, environmental benefits. However, these benefits are likely to be implicitly treated as zero unless their dollar value is somehow estimated. So, how much are they worth? Since people do not revealed their willingness to pay for them through their purchases or by their behavior, the only option for estimating a value is by asking them questions.. However, the fact that contingent valuation method is based on asking people questions, as opposed to observing their actual behavior, is the source of enormous controversy. The conceptual, empirical, the practical problems associated with developing dollar estimates of economic values on the basis of how people respond to hypothetical questions about hypothetical markets situations are debated constantly in the economics literature. However, contingent valuation researchers are attempting to address these problems, but they are far from getting to the point.. - 31 -.

(45) ADVANTAGES OF THE CONTINGENT VALUATION METHOD Contingent valuation method is enormously flexible in that it can be used to estimate the economic value of virtually anything. However, it is best able to estimate values for goods and services that are easily identified and understood by users and that are consumed in discrete units (e.g. user days of recreation), even if there is no observable behavior available to deduce values through other means.. Contingent valuation is the most widely accepted method for estimating total economic value, including all types of non use or passive use values. Contingent valuation can estimate used values as well as existing values, Option values and bequest values.. Though the technique requires competent survey analysts to achieve defensible estimates, the nature of Contingent valuation studies and the result of contingent valuation studies are not difficult to analyze and describe. Dollar values can be presented in term of a mean or median value per capita or per household or as an aggregate value for the affected population.. Contingent valuation has been widely used, and a great deal of research is being conducted to improve the methodology, make results more valid and reliable, and better understand its strengths and limitations.. - 32 -.

(46) REVELED PREFERENCE APPROACH This is a method by which it is possible to discern the best possible option on the basis of consumer behavior. Essentially, this means that the preferences of consumers can be revealed by their purchasing habits. Revealed preference theory came about because the theories of consumer demand were based on a diminishing marginal rate of substitution (MRS).This diminishing rate MRS is based on the assumption that consumers make consumption decisions based on their intent to maximize their utility. While utility maximization was not a controversial assumption, the underlying utility functions could not be measured with great certainty. Revealed preference theory was a means to reconcile demand theory by creating a means to define utility functions by observing behavior.. - 33 -.

(47) 2.2 STUDIES USING CONTINGENT VALUATION METHOD TO VALUE COST OF ILLNESS OF MALARIA In a study done in Tanzania by Wiseman and her colleagues to see the difference in Willingness to pay for artemisinin-based combinations or monotherapy, they found out that families who live in an area where the drug resistance to monotherapy is very high were willing to pay more for more effective artemisinin-based combination therapies than the monotherapy (Wiseman et al., 2005).. In a similar study done in Burkina Faso, people living in the town were more willing to pay for the malaria vaccine against Maternal Malaria and childhood malaria than those living in the rural area (Sauerborn et al., 2005).This maybe those that live in the town knows the implication of malaria and hence are more educated than those in the rural area. A study in Nigeria also shows that people preferred and were willing to pay more for a vaccine that was well tolerated, even if its effectiveness and duration of protection against malaria were lower than those of a product that caused severed adverse effects (Udezi, W. A., et al., 2010).. - 34 -.

(48) 2.3 STUDIES USING CONTINGENT VALUATION METHOD TO VALUE COST OF ILLNESS OF OTHER DISEASES In a willingness to pay study, mothers were willing to pay $238 more for a vaccine that provides 90% protection for genital warts relative to a vaccine that provides no protection against wart (Brown et al., 2009). In a similar study done in Malaysia, 68% mothers were willing to accept to be vaccinated with human papillomavirus vaccine (HPV) and 56% for their daughters and sons (Sam et al., 2009). In 2004, Parents and community members were willing to pay amounts varied from $100 to prevent 1 episode of otitis media and $500 to reduce the risk of meningitis from 21 in 100,000 to 6 in 100,000 for a pneumococcal conjugate vaccine (Anne et al., 2004). Also for an immunization program in Bangladesh, 63-70% educated mothers were willing to pay for the vaccine (Kamal et al., 1995).. A substantial portion of Canadian patients with ovarian cancer prefer to be treated with doxcetaxel instead of paclitaxel for the management of their disease and would be willing to pay a portion of the incremental cost (Dranitsaris et al., 2004).. Another study in Canada reveled that diabetes patients prefer inhaled insulin than the injection insulin and they would be willing to pay a substantial amount per month to use it (Hamid Sadri et al, 2005).. A study done in the States shows that parents and community members assigned relative high values to prevent meningitis, pneumonia and complex otitis media. Pneumococcal conjugate vaccine has a cost effectiveness ration in the range of other widely used health interventions ( Proser et al., 2004).. In a study done in Taiwan by Tang et al., 2009, mothers were willing to pay more for the vaccination of their daughters than to themselves. This is similar to the study done by J.T.Liu et al., 2000, where mothers were willing to pay twice for their children to protect them from a cold. - 35 -.

(49) In another study done in Japan using the contingent valuation method shows that Japanese men were willing to pay prostate cancer screening with prostate specific antigen (Yasunaga, 2008). A Study in Sweden in which they used contingent valuation method shows that willingness to pay for on demand and prophylactic treatment for severe hemophilia revels that the point estimates of Willingness to pay were lower for low income people but however, the differences were not found to be statistically significant (Carlsson et al., 2004).. - 36 -.

(50) Table 2.1: Studies using willingness to pay to value other diseases WTP APPROACH. MAIN FINDINGS. DISEASE. AUTHORS. COUNTRY. YEAR. Cancer prevention. Enforced Environmental regulations and implemented clinical practice guidelines. Cancer. Hunt et al.. Maryland, USA. 2009. Mass Screening. Future oriented life saving effects gained through Prostate cancer screening. Prostate Cancer. Yasunaga. Tokyo, Japan. 2008. Artemisinin-bases combination Therapy (ACT). WTP for ACT was less than its real cost. Malaria. Saulo et al.. Tanzania. 2008. Inhaled Insulin. Diabetes patients preferred inhaled insulin over insulin injection. Diabetes. Sadri et al.. Ontario, Canada. 2005. Hypothetical Malaria Vaccine. Males has a higher willingness to pay than females. Malaria. Rainer Sauerborn et al.. Burkina Faso. 2005. Docetaxel. Docetaxel instead of paclitaxel preferred to be treated on patients with ovarian Cancer.. Ovarian Cancer. Dranitsaris et al.. Ontario, Canada. 2004. On demand and prophylactic Treatment. Willingness to pay for Prophylaxis was greater in all possible subsets.. Severe Hemophilia. Carlsson et al.. Sweden. 2004. Health state prevented by pneumococcal Conjugate Vaccine. Parents and community members assign relatively high values in preventing Pneumococcal diseases.. Pneumococcal Infection. Prosser et al. USA. 2004. Quality of Life and health state Utilities. Skin diseases are associated with substantial reductions in quality of life. Psoriasis and atopic eczema. Lundberg et al.. Uppsala, Sweden. 1999. - 37 -.

(51) In conclusion, malaria constitutes a major burden on individuals and on the community in low income countries and pregnant women and children under five are the most vulnerable to the disease. It is on world record that the resistance of antimicrobial drugs is proving to be a challenging problem. The best and the most widely used drug for treating malaria has been on the decline. Newer antimalarial were discovered in the effort to tackle the problem but all these drugs were expensive or have undesirable side effects.. However, for that being the case scientist and politicians have implemented numerous programs to fight against this infectious disease which causes millions of death each year in the world and most of the death occurs in Sub-Saharan Africa. According to some malaria vaccine researchers, the problem will remain unless an effective vaccine becomes available.. - 38 -.

(52) CHAPTER THREE METHODOLOGY. 3.1 CONCEPTUAL FRAMEWORK Independent Variables. Dependent Variables. - 39 -.

(53) Willingness to pay (WTP) is the measure of the value an individual would place on reducing risk of death or illness. It is the maximum dollar amount the individual would be willing to give up in a given hypothetical risk reducing situation.. The framework below will be used to measure the influence of independent variables on WTP, which is the dependent variable. The empirical model was used by Sauerborn in 2005 in a similar study.. WTP = β0+β1X1 + β2X2 +…………………..+βn-1Xn_1+βnXn Where WTP= Willingness to pay (dependent variables) Β0 = Intercept βi = Coefficient of explanatory variables Xi = Explanatory variables (individual and household factors) Where i= 1, 2, …, n-1, n. - 40 -.

(54) 3.2 Hypotheses Hypothesis of the study are: 1. Socio-economic variables are determinants for willingness to pay for malaria vaccine. 2. Socio-demographic variables are determinants of willingness to pay for malaria vaccine. 3. Previous experience of malaria is determinants of willingness to pay for malaria vaccine.. - 41 -.

(55) 3.3 Operational Definitions of Study Variables Dependent Variable Willingness to pay (WTP) Willingness to pay (WTP) was a measure of how much the population was willing to pay for the Hypothetical Malaria Vaccine. The household heads were asked how much they will be willing to pay for themselves, their wife and children. Log_WTP was used in the regression so that a normal P-P plot of regression standardized residual can be obtain. The amount of the WTP was measured in GMD. Independent Variables. Socio-demographic variables Age: As for Age, it was divided into four groups. Where those that are less than 20 years or equal to 20 years were coded as 1.Those that are within the age of 21-30 were coded as 2.Those that are within the age group of 31-40 were coded as 3 and finally those that are within the group 41-50 were coded as 4. Gender: Gender is normally divided into two groups, male and female. Male was coded as 1 and female was coded as 2. Marital Status: We divided the marital status into five groups where 1 was coded as single, 2 for marital status monogamy, 3 for divorced, 4 for widowed and 5 for married polygamy. Education: The educational status was divided into six groups where 1 was coded as lower than elementary school level, 2 was coded as elementary school, 3 was coded as junior high school, 4 was coded as senior high school, 5 was coded as university education and 6 was coded as graduate school. Occupation: The occupational group was divided into three groups where 1 was coded as the teachers, 2 were coded as those in the financial sectors and 3 were coded as others. Vaccine receiver: Who vaccine is the variable which means who receives the vaccine, the household head, wife or the children. This group was divided into three categories where 1 was coded as the household head, 2 were coded as the wife and 3 were coded for the children. However, in our. - 42 -.

(56) questionnaire, it is only the household heads who were asked the WTP for themselves, their wives and their children.. Socio-economic variables Monthly household income: This group of variable was divided into seven groups. 1 was coded as those that their monthly household income is equal to or less than 1999 dalasis. 2 was coded as those that monthly income range from 2000 to 4000 dalasis, 3 was from 5000 to 70000 dalasis, 4 was from 8000 to 10000, 5 was from 11000 to 13000, 6 was from 14000 to 16000 dalasis and 7 was coded as greater or equal to 17000 dalasis. All the money was express in Gambian currency, dalasi.. Monthly household expenditure: Monthly household expenditure was a continuous variable during the study but was later converted to categorical variable. For the categorical variable of the monthly household income, it was divide into five groups.1 was coded as less than 1000dalasis, 2 was coded as 1000dalasis to 5999dalasis, 3 was coded as 6000dalasis to 10999dalasis, 4 was coded as 11000dalasis to 15999dalasis and 5 was coded as greater than or equal to 16000dalasis.Again all the money were express in Gambian currency (GMD).. Last medical expenditure: Last medical expenditure was also a continuous variable during the study but was later converted to categorical variables. It was divided into five groups where 1 was coded as less than 300dalasis, 2 was coded as 300dalasis to 599dalasis, 3 was coded as 600dalasis to 1999dalasis, 4 was coded as 2000dalasis to 2999dalasis and 5 was coded as equal to or greater than 3000dalasis.. Number of Household size: Household size was a continuous variable but was converted into categorical variables during the analysis process. It was divided into four groups. 1 was coded as - 43 -.

(57) household size between 1 and 3, 2 was coded as between 4 and 6, and 3 was coded as between 7 and 9 and 4 was coded between 10 and 12.. Number of Household children aged less than 6: Household children size that are less than six years old in the family were also collected as a continuous data but was converted as a categorical during the analysis process. It was divided into four groups. 1 was coded as household that do not have children less than 6, 2 was coded as household that has only one child less than 6 years old, 3 was coded as household that has two children that are less than 6 years old and 4 was coded as household that has three children that are less than 6 years old.. Number of Household female size: This is the number of females in the family. The number of females in the family was divided into four groups. 1 was coded as household female size between 1 and 3, 2 was coded as household female size between 4 and 6, 3 was coded as household female size between 7 to 9 and 4 was coded as household female size between 10 to 12.. Duration of stay in their Homes: This is the number of years the respondent live in their place. It was a continuous variable but was converted to categorical variable during the analysis process. It was divided into four groups in which 1 was coded as less or equals to 20 years of stay in a place, 2 was coded as 21 years to 30 years of stay in a place, 3 was coded as 31 years to 40 years of stay in a place and 4 was coded as 41 years to 50 years of stay in a place.. - 44 -.

(58) Medical History Variable Previous experience of malaria: This is the number of times the respondent have malaria in the year. 1 was coded as once in a year, 2 were twice in a year, 3 were thrice in a year and 4 were fourth times in a year.. - 45 -.

(59) Table 3.1 Operational definitions of dependent and independent variables Variable Dependent Variable Willingness to pay (WTP) log_wtp. Definition. Nature of the Variable. Willingness to pay for the Household head, wife and children. The amount is in Dalasis(GMD). Categorical. Independent Variables Socio-demographic variables Age. Age in years. Continuous. Gender. Male=1, female=2. Categorical. Marital Status. Single=1, married-monogamy=2, divorce=3, widowed=4, married-polygamy=5. Categorical. Education Occupation. Lower than elementary school=1, elementary school=2, junior high school=3, senior high school=4, university=5, Graduate school=6 Teacher=1, financial sectors=2, others=3. Vaccine receiver. Household head=1, wife=2, children=3. Categorical. Monthly household income. D1000-1999=1, D2000-D4999=2, D5000D7999, D8000-D10999=4, D11000=D13999=5, D14000-16999=6, ≤D17000=7. Categorical. Monthly household expenditure. Monthly household expenditure in dalasis. Last medical expenditure. Last medical expenditure in dalasis. Continuous. Number of Household size. Household size in person. Continuous. Categorical. Categorical. Socio-economic variables. Number of Household children Household children size<6 in person aged less than 6. Continuous. Continuous. Number of Household female size. Household female size in person. Continuous. Duration of stay in their homes. Duration of stay in years. Continuous. Number of times the respondent have malaria in a year. 1 times in a year=1, 2 times in a year=2, 3 times in a year=3, 4 times in a year=4. Categorical. Medical History Variable Previous experience of malaria. - 46 -.

(60) 3.4 Study Design and Subjects Willingness to pay (WTP) is a common method to estimate monetary values for health care interventions. WTP is also known as contingent evaluation. In the WTP approach, the maximum amount that an individual is willing to pay to obtain a good is elicited using a bidding game method. The bidding game present the respondent with an amount and ask whether she is willing to pay that amount. Depending on the answer given, respondent are asked to bid up or down using the options in the questionnaire until the maximum number is reached. The WTP technique was original developed by an environmental economists, but is increasingly used in health economics (Grutters et al, 2009).. The preference of the study population was determined by a bidding game, a widely accepted method for accessing consumer stated preferences (as opposed to revealed preferences through expressing demand at given process), in the absence of a market for a product. Bidding games produce reliable results even in illiterate populations (Sauerborn et al., 2005).. In this study, a structured willingness to pay (WTP) questionnaire was administered to those already diagnosed malaria patients and household head throughout the survey.. This study will help government, researchers and funding agencies with the basis for intervening in the market and setting priorities in malaria vaccines. Such strategies might include subsidizing payments, targeted subsidies or providing free drugs to the poor.. The exclusion criteria were household head above 50 years of age were not interview. The inclusion criteria was to seek the respondent consent first before interviewing them and also it was only already adult diagnosed malaria patients were interview at the Royal Victoria teaching Hospital (RVTH) in. - 47 -.

(61) Banjul which is the main referral hospital in The Gambia. Adult household heads in the community were also interviewed in their compounds and also in work places. They were interviewed by a trained interviewer in September 2010 while waiting for their malaria drugs at the outpatient clinic at RVTH.. A questionnaire was designed to elicit respondent WTP for a hypothetical malaria vaccine in The Gambia capable of preventing maternal malaria and childhood malaria. One hundred already diagnose malaria patients were given the questionnaire to fill out and one hundred household head were also given the questionnaire to fill. However, the household heads and the patients were asked their willingness to pay for their spouse and their children. If the respondent is a woman, she is also equally asked their willingness to pay for their husband and children.. Willingness to pay for the vaccines were elicited by a bidding method in which respondent being asked how much they would be willing to pay for the vaccine against maternal malaria and childhood malaria by giving them the first bidding amount which is 1000 dalasis. If the respondent‟s answer to the first bid offered which is 1000, the interviewer then increases the bid to 25% and asked the same question again. If the respondent still wants to bid more than the amount then the amount is increase to 25% until they reach at the last bidding amount.. However, if the respondent rejects the initial bid, the intervierver decreases the amount to 25%. If the respondent still rejects the amount, then the bidding is then reduced again by 25%. This continued until the respondent reached its least bidding amount for the vaccine.. - 48 -.