Clinical development, registration, and introduction of human rotavirus vaccine: The Latin American experience

Rotavirus (RV) is the leading cause of severe gastroenteritis (GE) among infants and young children worldwide, accounting for 453,000 deaths in children aged <5years. In Latin America rotavirus causes an estimated 15,000 deaths annually and accounts for 20–70% of acute gastroenteritis cases requiring hospitalization. This results in an estimated annual cost of approximately US$86 million. The most common G type has been G1 (∼50%), followed by G4, G3 and G9, although regional and temporal variations are significant. There are currently two effective rotavirus vaccines: a single-strain, human attenuated-based (RotarixTM, GlaxoSmithKline Biologicals), and a five-strain, bovine-human reassortant vaccine (RotaTeqTM, Merck and Company). The pioneering strategy behind the development and licensure of RotarixTM was part of a new paradigm for global vaccine research and development focusing on introduction first in countries with greatest medical needs. Rotarix™ demonstrated high efficacy and a good safety profile in Phase II and III clinical trials performed in Latin America. In the pivotal phase III study involving 11 Latin American countries a 2-year efficacy of 81% (95% CI: 71–87) was achieved against severe rotavirus acute gastroenteritis. A high protective efficacy was observed against severe rotavirus gastroenteritis caused by G1 and non-G1 strains. RotarixTM proved to be safe regarding intussusception (IS) in a two-dose vaccine schedule beginning at 6–12weeks of age.