Rotavirus is the leading cause of severe, dehydrating diarrhoea in children less than 5 years old. Rotaviruses are a double-stranded RNA virus of the genus Reoviridae. The virus is composed of a triple-layered viral particle. The outermost viral layer contains the structural viral proteins VP7 and VP4 that are considered important for protective immunity. At least 11 different VP7 antigens (G-types) and 11 different VP4 antigens (P-types) have been identified. Although the viral strains show considerable diversity, 5 serotypes (G-P combinations) are responsible for the majority of human rotavirus disease. In infants aged less than 3 months, the first exposure to rotavirus frequently results in gastroenteritis, with secretory diarrhoea, a loss of fluids and electrolytes, and shock that can be fatal.
Following infection a large amount of virus is shed in the stools and vomit with transmission occurring mainly by subsequent oral ingestion of contaminated materials. The vast majority of children are infected before the age of 3 years, and in most developing countries before the first birthday. The universal occurrence of rotavirus infections indicate that unlike many infectious diseases spread by faecal contamination, clean water supplies and good hygiene do not significantly lower the transmission rate.
Vaccine development has focused on live attenuated rotavirus strains of human or animal origin which mimic those found in human disease. Currently marketed vaccines include a monovalent human rotavirus vaccine and a pentavalent bovine-human reassortant rotavirus vaccine propagated in cell culture. Both vaccines are administered orally.
Rotavirus Vaccine Standardization
WHO recommendations on live attenuated rotavirus vaccines which describe the production, quality control, nonclinical, and clinical expectations for existing vaccines and candidates under development were adopted by the Expert Committee on Biological Standardization in 2005.
Guidelines to assure the quality, safety and efficacy of live attenuated rotavirus vaccines (oral), TRS 941, Annex 3
No WHO reference materials for rotavirus vaccines are currently available.
WHO workshop in Training Performance of Rotavirus Vaccine Potency Testing, NIBSC, Potters Bar, UK, 19-23 March 2007
Report of a meeting on quality, safety and efficacy specifications for live attenuated rotavirus vaccines, Mexico City, Mexico, 8-9 February 2005
IABS Scientific Workshop on Neurovirulence Tests for Live Virus Vaccines, WHO, Geneva, Switzerland, 31 January-1 February 2005
Prequalified rotavirus vaccines
Rotavirus vaccines are prequalified for procurement by UN organizations: