DD had confirmed rota-virus when she was 18months old, this hospitalised her twice in a month for 3 weeks in total being NGT and IV'd. We were told by the paed to get her to have the serum after 12 months as if she was to be exposed after 12 months she had no immunity. So we had her serumed at 2.5 ...3 doses . She has been admitted this year for Rota virus thankfully this was just a weeks admittance, I think there is so many differing strains they cant keep up with it.