Rotavirus genotypes in children in the Basque Country (northern Spain) over a 13-year period (July 1996-June 2009)

To describe the circulation dynamics of human rotavirus genotypes in a region of southern Europe over a 13-year period. The G- and P-types of rotavirus isolates of patients aged less than 5 years were analyzed using multiplex, reverse transcription polymerase-chain reaction. Of 1,538 isolates investigated, a combination of individual G-and P-types was obtained in 1,368. The most prevalent combination was G1[P8] (57.5% of the genotyped strains), which circulated in all seasons and predominated in nine out of 13 seasons. The strains G2[P4] (14.4%), G3[P8] (8.3%), G4[P8] (5.5%) and G9[P8] (13.4%) circulated intermittently. G4[P8] strains were frequently detected in the 1990s but only sporadically after 2000. G9[P8] strains emerged from 1997-1998 and became dominant in the winters of 2005-2007. G2[P4] strains were predominant in 2003-2004, before the rotavirus vaccines were commercialized. Unusual combinations of common G-and P-types and the presence of unusual G- and/or P-types (G6[P14], G8[P8], G8[P14] and G12[P8]) were rarely observed (<1%). We found no differences in hospitalization due to distinct genotypes. G-types G1-G4 and G9 represented >99% of circulating rotaviruses over a 13-year period. Therefore, vaccine efficacy in this region can be expected to be high.