Rotavirus vaccines: a long and difficult journey

Diarrhea is the second cause of death worldwide. The main causative agent in infants and children less than 5 years is rotavirus. Consequently, for the World Health Organization and the Global Alliance for Vaccines and Immunization (GAVI), rotavirus vaccination is an urgent priority. The global distribution of rotavirus serotypes varies from country to country, but in 80-90% of cases is caused by five types: G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8]. Currently, two rotavirus vaccines are available, an attenuated monovalent G1P[8] vaccine, and a pentavalent human-bovine recombinant vaccine containing five strains of bovine WC3 rotavirus, four with a gene codifying the VP7 protein of human rotaviruses G1, G2, G3 and G4, and a fifth expressing the VP4 P[8] genotype.