The need for safe and effective vaccines to reduce morbidity and mortality 
caused by rotavirus gastroenteritis in children is well-known. A live attenuated 
monovalent rotavirus vaccine (Rotarix) containing human rotavirus strain RIX4414 
of G1P1A P[8] specificity is being developed to meet the global need. An 
overview of RIX4414 trials in developed and developing settings is presented for 
3 selected trials conducted in Finland (pilot study), Latin America (Brazil, 
Mexico and Venezuela) and Singapore involving 5024 infants. The vaccine was 
well-tolerated, with no increase in any solicited symptoms as compared with the 
placebo. After 2 doses, 61-91% of vaccinated infants developed 
rotavirus-specific IgA antibodies. There was no interference with immunogenicity 
of coadministered routine pediatric vaccines. Rotarix significantly reduced 
rotavirus gastroenteritis episodes and rotavirus-related hospitalizations in 
vaccinated infants compared with placebo recipients (P < 0.05). Vaccine efficacy 
was observed against severe rotavirus gastroenteritis caused by G1 and non-G1 
types including the emerging G9 type (P < 0.05) in Latin America. These results 
show prospects for widespread use of Rotarix to reduce rotavirus disease burden 
and warrant continued worldwide evaluation.