Dengue viruses (Flavivirus) are mosquito-borne human pathogens with a worldwide prevalence. There are four antigenically-related dengue virus serotypes, DEN-1 to DEN-4, which can cause serious problems of morbidity and mortality. Dengue is emerging rapidl y as one of the most important public health problems in countries of the Asia-Pacific region with nearly 1.8 billion people in the region at risk, compared to an estimated total of 2.5 billion globally (WHO 2007). In India, dengue is now re-emerging as o ne of the most important health problems with many outbreaks reported in different parts of the country during the past decade. The disease has resulted in widespread social and economic problems, especially among the poor who are the most vulnerable grou p. The lack of a dengue vaccine and antiviral drug makes it difficult for governments to control and manage the disease, although considerable efforts have been made, including vector control, sanctions, law enforcement and public education. To develop a vaccine against dengue infection and to establish a cost-effective system for large scale production of dengue vaccine(s) is important. We propose therefore an Indo-Norwegian project to (1) develop a cost-effective and safe production system for dengue va ccine via a tobacco chloroplast expression system and (2) produce a tetravalent vaccine against dengue by expressing the host cell receptor binding dengue envelope domain III of the four antigenic serotypes alone or together in tobacco chloroplasts. The f unctionality of the chloroplast-derived tetravalent dengue vaccine and the economic and social benefits of the chloroplast expression approach will be evaluated. All the proposed work will be conducted jointly by Norwegian and Indian partners and with the participation of an Austrian collaborator. This initiates our long-term collaboration on vaccine development and a cost-effective plant-based production system.