Australian Rotavirus Surveillance Program annual report, 2013

This report from the Australian Rotavirus Surveillance Program, together with collaborating laboratories Australia-wide, describes the rotavirus genotypes responsible for the hospitalisation of children with acute gastroenteritis during the period 1 January to 31 December 2013. During the survey period, 1,035 faecal samples were referred for rotavirus G and P genotype analysis. Of these 828 were confirmed as rotavirus positive. A total of 503 specimens were collected from children under 5 years of age, while 325 were from older children and adults. Genotype analysis of the 828 rotavirus samples collected from both children and adults revealed that G12P[8] was the dominant genotype in this reporting period, identified in 33% of strains nationally. Genotype G3P[8] was the second most common strain nationally, representing 31% of samples, followed by genotype G2P[4] (14%). This represents the first report where G12P[8] strains are the major cause of disease in this population. The genotype distribution was slightly altered when the analysis was restricted to samples collected from children under 5 years of age, with G3P[8] being the dominant genotype (39.2%) followed by G12P[8] as the second most common genotype (31%). Fluctuations in genotype distribution were also observed based on the vaccine type in use. Genotype G12P[8] was more common in states and territories using RotaTeq, while G3P[8] was more common in the locations using Rotarix. This survey highlights the yearly fluctuations in rotavirus genotypes observed since vaccine introduction, with changes in dominant genotypes an annual event. The emergence of G12P[8] as the dominant genotype further illustrates the ongoing changes in the wild type rotavirus population evident in the Australian population since vaccine introduction.