Economic Challenges and Impact
Introducing a schistosomiasis vaccine would introduce significant economic benefit to countries impacted by the parasitic illness, including Brazil, China, Egypt, the Phillipines and several countries in Sub-Saharan Africa. Improving the quality of life of many young children and working-age people in these areas has the potential to offer far-reaching benefits to the host countries. As the World Health Organization attests, it is important to remember these end-goals when considering the cost of what many researchers consider the final stages towards development of a Schistosomiasis vaccine [20].
Although several groups have started clinical trial testing, the most difficult and costly portion of vaccine development is yet to come. As already mentioned, current work in France, Egypt, and Brazil is being conducted under Phase I and Phase II clinical trials to study glutathione-S-transferase (GST) and other vaccine candidates [21]. However, the burden of cost is far from complete. Phase I and Phase II trials are usually done on a smaller scale to test safety and basic efficacy of vaccines, whereas Phase III clinical trials include construction and validation of manufacturing capacity and licensure, which are both very expensive. From Phase I and II trials to Phase III, costs rise dramatically, often including 50-60% of all costs incurred during vaccine development research [22]. For example, just in 2002, costs to develop pharmaceutical products and vaccine licensure were in the ranged of $500 million based on historical information [22]. Therefore, present-day estimates to develop a vaccine range from $750 million to about $1 billion.
Another major contributor to cost, as well as a logistical difficulty with vaccination efficacy, is the fact that these clinical studies will have to be performed in rural endemic areas where medical and healthcare facilities are often inadequate [23]. This suggests that a significant investment in both infrastructure and training of personnel will be needed in rural areas, further increasing expenses. In addition, to monitoring the duration of protection of the vaccine and assessing any possible immunopathologic effects, these groups may have to remain in the areas for several years [23]. In summary, administering the vaccine alone is very expensive, but in the end it will only be a fraction of the overall vaccination program.
There are, however, significant human, national and international economic benefits associated with vaccine development. For one, introducing an effective vaccine has the potential to eliminate disease and morbidity-related paralysis in millions of people [24]. The reduction in morbidity and disease will result in healthier populations that may contribute to society economically as workers, and socially as community leaders, and more.
Vaccination would provide a significant human benefit by improving the health and productivity of young populations, thus having positive effects on national economic productivity in countries already suffering financially. Many vaccine researcher express the thought that the initial target group for vaccination may be infants and children who have never been infected or who have only recently become exposed to the threat of eggs. This strategy has the potential of cutting costs, especially if studies continue to show that adults exhibit some or very strong immunity with current drug treatments. More importantly, it provides children with the possibilities of becoming economically and infrastructurally-productive teens and adults.
The attention the vaccination effort will receive may help to finance the cost of the campaign and to introduce other economic investments to those countries. Philanthropic efforts, like those initiated and headed by the WHO, TDR, CDC and UNICEF [20, 24], may help to introduce infrastructure for basic clinics and healthcare facilities and to reinforce attention to eliminate other diseases, such as Leishmaniasis and Malaria [23]. Finally, although quantifying the amount of money earned from reducing morbidity and co-morbidities associated with schistosomiasis infection is beyond the scope of this project, there is no doubt that the individual, familial and national economies will benefit from the reduced burden of schistosomiasis.
Medical Challenges/Impacts
As mentioned above, because there are so many challenges encountered during new pharmaceutical and vaccine development, it is important to start with the end in mind. Todd and Colley clearly state this when saying that, “developing a licensed vaccine project for neither the underfunded nor the weak of heart” [23]. Several important challenges to vaccine success include stability, delivery and administration, and efficacy. There are, however, many medical benefits associated with the vaccination strategy. These include the ideal elimination of schistosomiasis; improved health and quality of life of the millions of people infected with this parasite, especially children; possible establishment of more healthcare facilities and access to medical care; better sanitation and health education; strengthening of departments of health in affected countries; and access to an immense library of research that may lead to future scientific and medical discoveries.
Stability of the vaccine, the delivery method and the administration of vaccination programs are difficult medical challenges in the search for an adequate schistosome vaccine because they are within the context of Phase III clinical trials that must be carried out largely in rural areas [25]. Stability of the vaccine, or viability and usability, will be very important in areas such as Egypt, Brazil, Sub-Saharan Africa and the Caribbean Basin [21]. If not stable at high temperatures, the vaccine will have to be stored at low centigrade temperatures. This will require refrigerators that may have to run on generator power in places without electricity. In summary, the stability of the vaccine is important to ensure that, in clinical trials and if licensure is acquired, a truly viable vaccine is administered.
The delivery method and administration of vaccination programs also pose several challenges. As mentioned above, delivering the vaccine to rural areas is a great challenge. Vehicles equipped to transport vaccines, medical personnel and researchers will be necessary. Administration of vaccination may pose difficult cultural/societal problems as well. There may be trust and cultural block issues between citizens and medical personnel. And training interpreters and staff will be necessary and costly, especially if the program is to last for months.
Further complicating the issue is the fact that the three main species of schistosomes targeted for vaccination—mansoni, japonicum and haematobium—all require separate vaccination programs because they have, at least until recently, shown to be different antigenically. This means that the problems encountered to develop a vaccine for one species, already medically daunting, will triple when creating a world-wide vaccination program [21].
Nothing, however, can be done without the end in sight. It is important to remember the why’s and the reasons to undertake the search for a schistosomiasis vaccine. Unlike present drug treatments, a successful vaccine will more fully protect against long-term reinfection, may allow for the creation and maintenance of healthcare facilities in countries who benefit from the program, will improve the health and quality of life of millions of people worldwide, especially young children, and may help to strengthen departments of health in target countries.
Finally, access to an immense library of research will be of great value because this may allow vaccine developers to improve the administration/efficacy of the vaccine and may also lead to unseen benefits, including future medical discoveries. For instance, when Ogilvie et al. studied experimental Schistosoma infection, they made observations about the production of reaginic antibodies during the experiments. This led to the notion that the antibodies may function during the immune defense against the parasites [26]. When immunoglobulin E was discovered, studies rapidly followed by the demonstration of elevated IgE levels in helminth infection. The discovery has since had several medical and scientific applications for treatments and research of parasitic and allergic illnesses [26]. Thus, the schistosome vaccination program may lead researchers to unknown medical and/or scientific discoveries and advancements.
Political Challenges
Getting local and national governments to join the vaccination effort is feasible, but maintaining interest and involvement will be difficult. Many countries, especially those in sub-Saharan Africa, will have greater difficulties implementing and sustaining a vaccination program due to the fact that governmental stability is lacking in many of the target areas. In addition, support for the vaccination programs will be difficult especially since political commitment most often relates to economic commitment.
The use of international loan programs, the lowering of poverty rates, and external political commitment from the international community is necessary for a successful campaign. Availability of economic resources has promoted greater political commitment for wide-scale chemotherapy in countries such as Egypt, China, Prazil, the Phillippines, Tunisia and Saudi Arabia. Key factors contributing to success of these programs were concurrent socioeconomic development, national commitment and continued economic support, in several cases through loans from the World Bank [27]. It follows that wide-scale chemotherapy campaigns in sub-Saharan countries and other third-world nations had greater difficulty economically. Pilot-programs showed promising results, only to flounder and often disappear when foreign assistance is ended [27]. An international vaccination campaign will be no different.