Rotavirus vaccines: development and use for the prevention of diarrhoeal disease

Rotavirus causes annually 600 000 deaths off young children worldwide, main ly in developing countries. The burden of rotavirus disease is significant also in developed countries and has not diminished with improved hygiene. N atural protective immunity against severe rotavirus disease is built UP dur ing the first 2-3 years of life. Likewise, studies with live attenuated ora l rotavirus vaccines have shown that the majority of severe episodes of rot avirus diarrhoea are preventable by oral immunization. Candidate rotavirus vaccines were first developed by tissue culture adaptation and attenuation of bovine and rhesus rotaviruses, both of which share the inner core VPG gr oup antigen with human group A rotaviruses. Subsequently, such heterologous rotaviruses were improved for use as human vaccines by reassortment with h uman rotaviruses; the resulting reassortants express human rotavirus VP7 su rface antigens. A rhesus-human reassortant tetravalent (RRV-TV) rotavirus v accine was licensed in the USA in 1998, and is recommended for universal im munization of healthy children; licensure in Europe is also imminent. In Fi nland, this vaccine has prevented 90% of severe episodes of rotavirus gastr oenteritis. Protective efficacy of RRV-TV vaccine in developing countries i s lower and a more intensive immunization schedule may be needed. Several o ther candidate rotavirus vaccines, including bovine-human reassortants, are being investigated.