Dengue vaccines: Problems & prospects

639 Dengue virus (DV) infect ion is most ly asymptotic or produces a mild self-limiting acute febrile illness, dengue fever (DF), and a lifethreatening severe illness, dengue haemorrhagic fever (DHF) with minor or major bleeding from different sites. DHF has emerged as the most important arbovirus disease in man in the last three decades. It has been estimated that about 50 to 100 million cases of DF occur every year with about 250,000 to 500,000 cases of DHF . During epidemics of dengue, attack rates population 40 to 90 per cent among susceptible of whom a very large proportion is of children. The year 2001 witnessed unprecedented global dengue epidemic activity in the American hemisphere, the Pacific islands and continental Asia. During 2002, more than 30 Latin American countries reported over 10,00,000 DF cases with large number of DHF cases. This has been followed by extensive epidemics of DHF in several parts of India during 2003. Dengue vaccines: Problems & prospects