Live attenuated tetravalent dengue vaccine

The development of a live attenuated tetravalent dengue vaccine is currentl y the best strategy to obtain a vaccine against dengue viruses. The Mahidol University group developed candidate live attenuated vaccines by attenuati on through serial passages in certified primary cell cultures. Dengue serot ype 1, 2 and 4 viruses were developed in primary dog kidney cells, whereas dengue serotype 3 was serially passaged in primary African green monkey kid ney cells. Tissue culture passaged strain viruses were subjected to biologi cal marker studies. Candidate vaccines have been tested as monovalent (sing le virus), bivalent (two viruses), trivalent (three viruses) and tetravalen t tall four serotype viruses) vaccines in Thai volunteers. They were found to be safe and immunogenic in both adults and children. The Mahidol live at tenuated dengue 2 virus was also tested in American volunteers and resulted in good immune response indistinguishable from those induced in Thai volun teers. The master seeds from the four live attenuated virus strains develop ed were provided to Pasteur Merieux Connaught of France for production on a n industrial scale following good manufacturing practice guidelines. (C) 20 00 Elsevier Science Ltd. All rights reserved.