Estimating potential demand and supply of dengue vaccine in Brazil

Prioritizing the vaccine supply chain issues of developing countries using an integrated ISM-fuzzy ANP framework

Purpose

Delivering vaccines to the children who need them requires a supply chain that is efficient and effective. In most of the developing countries, however, the unknown and unresolved supply chain issues are causing inefficiencies in distributing vaccines. There is, therefore, a great need in such countries to recognize the issues that cause delays in vaccine delivery. With this purpose, the present study aims to identify and analyze the key issues in the supply chain of basic vaccines required to immunize children in developing countries.

Design/methodology/approach

Based on a field survey of three states of India, in-depth review of relevant literature and experts’ opinions, 25 key issues were recognized as factors of the vaccine supply chain (VSC) and categorized into five main domains. Using integrated interpretive structural modeling and fuzzy analytic network process approaches, the issues have been prioritized to determine their relative importance in the VSC. In addition, a sensitivity analysis has been performed to investigate the priority stability of the issues.

Findings

The results of the analysis show that among the five domains of VSC issues, the economic domain with a weight of 0.4262 is the most important domain, followed by the management (0.2672), operational (0.2222), environmental (0.0532) and social (0.0312).

Research limitations/implications

This study focuses on the prioritization of VSC issues; therefore, the results of the present study can provide direction to the decision-makers of immunization programs of developing countries in driving their efforts and resources on eliminating the most important obstacles to design successful vaccination programs.

Originality/value

To the authors’ knowledge, this paper is first to provide a direction to the decision-makers in identifying and managing important issues through the use of an analytical approach.

Two-way assessment of key performance indicators to vaccine supply chain system in India

Purpose

The purpose of this paper is to identify the key performance indicators (KPIs) of vaccine supply chain of Universal Immunization Program (UIP) India, and measure their impact on vaccine supply chain performance improvement, so that results of this study can help the decision makers manage the activity and effectiveness of their resources in order to improve vaccine delivery performance and child immunization coverage.

Design/methodology/approach

The 41 KPIs in terms of four dimension of the balanced scorecard (BSC), i.e. financial, customer, internal process and learning and growth have been identified and validated from the literature and expert’s opinions. Further, the impact of internal process and learning and growth performance indicators on the vaccine supply chain performance improvement have been evaluated using two-way assessment. The rankings obtained using two-way assessment are then compared to DEMATEL approach to validate the results.

Findings

The results from the analysis reveal that “Enhancement in employee work satisfaction” (LG3=10.08 percent), “Enhancement in professional vaccine supply chain managers and leaders” (LG2 = 6.70 percent) “Improvement in planning and coordination in the supply chain” (LG9 = 6.57 percent) are the three critical performance indicators having maximum impact on vaccine supply chain performance improvement. The decision makers should give priority to these performance indicators to improve delivery performance and immunization coverage.

Social implications

This study focuses on the improvement in vaccine delivery performance, therefore, analysis and findings can be useful to government immunization programs of India to other developing nations to improve child immunization coverage.

Originality/value

To our knowledge, this paper is first to attempt to provide a direction to improve immunization coverage through vaccine supply chain performance indicators.

Challenges in reducing dengue burden; diagnostics, control measures and vaccines

Dengue is a major public health concern worldwide, with the number of infections increasing globally. The illness imposes the greatest economic and human burden on developing countries that have limited resources to deal with the scale of the problem. No cure for dengue exists; treatment is limited to rehydration therapy, and with vector control strategies proving to be relatively ineffective, a vaccine is an urgent priority. Despite the numerous challenges encountered in the development of a dengue vaccine, several vaccine candidates have shown promise in clinical development and it is believed that a vaccination program would be at least as cost-effective as current vector control programs. The lead candidate vaccine is a tetravalent, live attenuated, recombinant vaccine, which is currently in Phase III clinical trials. Vaccine introduction is a complex process that requires consideration and is discussed here. This review discusses the epidemiology, burden and pathogenesis of dengue, as well as the vaccine candidates currently in clinical development.

Country- and age-specific optimal allocation of dengue vaccines

Several dengue vaccines are under development, and some are expected to become available imminently. Concomitant with the anticipated release of these vaccines, vaccine allocation strategies for dengue-endemic countries in Southeast Asia and Latin America are currently under development. We developed a model of dengue transmission that incorporates the age-specific distributions of dengue burden corresponding to those in Thailand and Brazil, respectively, to determine vaccine allocations that minimize the incidence of dengue hemorrhagic fever, taking into account limited availability of vaccine doses in the initial phase of production. We showed that optimal vaccine allocation strategies vary significantly with the demographic burden of dengue hemorrhagic fever. Consequently, the strategy that is optimal for one country may be sub-optimal for another country. More specifically, we showed that, during the first years following introduction of a dengue vaccine, it is optimal to target children for dengue mass vaccination in Thailand, whereas young adults should be targeted in Brazil.

Dengue dynamics and vaccine cost-effectiveness in Brazil

Recent Phase 2b dengue vaccine trials have demonstrated the safety of the vaccine and estimated the vaccine efficacy with further trials underway. In anticipation of vaccine roll-out, cost-effectiveness analysis of potential vaccination policies that quantify the dynamics of disease transmission are fundamental to the optimal allocation of available doses. We developed a dengue transmission and vaccination model and calculated, for a range of vaccination costs and willingness-to-pay thresholds, the level of vaccination coverage necessary to sustain herd-immunity, the price at which vaccination is cost-effective and is cost-saving, and the sensitivity of our results to parameter uncertainty. We compared two vaccine efficacy scenarios, one a more optimistic scenario and another based on the recent lower-than-expected efficacy from the latest clinical trials. We found that herd-immunity may be achieved by vaccinating 82% (95% CI 58-100%) of the population at a vaccine efficacy of 70%. At this efficacy, vaccination may be cost-effective for vaccination costs up to US$ 534 (95% CI $369-1008) per vaccinated individual and cost-saving up to $204 (95% CI $39-678). At the latest clinical trial estimates of an average of 30% vaccine efficacy, vaccination may be cost-effective and cost-saving at costs of up to $237 (95% CI $159-512) and $93 (95% CI $15-368), respectively. Our model provides an assessment of the cost-effectiveness of dengue vaccination in Brazil and incorporates the effect of herd immunity into dengue vaccination cost-effectiveness. Our results demonstrate that at the relatively low vaccine efficacy from the recent Phase 2b dengue vaccine trials, age-targeted vaccination may still be cost-effective provided the total vaccination cost is sufficiently low.