K. Zaman (1) ([email protected]), D.A. Sack (1), Md. Yunus (1), S.E. Arifeen (1), Tasnim Azim (1), G. Podder (1), A.S.G. Faruque (10, S. Karim (20, S. Luby (10, and R.F. Breiman (1)
(1) ICDDR,B: Centre for Health and Population Research, GPO Box 128, Dhaka 1000, Bangladesh
and (2) Shishu Hospital, Sher-e-Bangla Nagar, Dhaka 1207, Bangladesh
A safe and effective rotavirus vaccine is urgently needed to reduce the enormous disease burden associated with illness due to rotavirus. Tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV) was associated with intussusception following introduction in the United States, leading to accelerated development of alternative vaccine candidates with a strong recommendation to study in parallel the safety and efficacy in developed and developing countries. Two new candidate vaccines have recently been shown to be highly effective and safe and have potential for the prevention of rotavirus-associated morbidity and mortality.
The first rotavirus vaccine study in Bangladesh was conducted with RRV-TV among infants in Matlab during 1998-1999. Safety, reactogenicity and immunogenicity studies with oral live human rotavirus (HRV) vaccine (RIX4414) among toddlers and infants with "all in one formulation" (vaccine and buffer in the same vial) were completed in urban Dhaka during 2002-2004. Another immunogenicity study among infants is ongoing with "commercial formulation" of HRV (vaccine and buffer in separate vials). The design of a proposed efficacy trial at Matlab surveillance area is also being presented.
The RRV-TV vaccine was safe and highly immunogenic. The human rotavirus vaccine (RIX4414) was safe and well-tolerated in toddlers and infants. The solicited symptoms were generally mild and of short duration. The immunogenicity of the vaccine with "all in one formulation" was low. This formulation is no longer developed. The results of immunogenicity study with "commercial formulation" are being analyzed. There were no cases of intussusception.
While the RRV-TV vaccine was safe and inmmunogenic within Bangladesh setting, its withdrawal by U.S. has impacted negatively the possible use of the vaccine in developing countries. Currently, only the HRV vaccine (RIX4414) is studied for safety and immunogenicity. Field effectiveness trials are needed to confirm the reported efficacy and safety elsewhere of the two new vaccine candidates. Effective vaccines are highly desirable in developing countries where the public-health disease burden is most devastating.
Acknowledgements: The studies were supported by the USAID, NVPO, PATH, WHO, and GSK.