Major reduction of rotavirus, but not norovirus, gastroenteritis in children seen in hospital after the introduction of RotaTeq vaccine into the National Immunization Programme in Finland

Universal rotavirus (RV) vaccination is expected to reduce hospitalizations for acute gastroenteritis (GE) of children by eliminating most of severe RVGE, but it does not have any effect on norovirus (NV), the second most common causative agent of GE in children. After the introduction of the RV vaccine into the National Immunization Programme (NIP) of Finland in 2009, we conducted a prospective 2-year survey of GE in children seen in Tampere University Hospital either as outpatients or inpatients and compared the results with a similar 2-year survey conducted prior to NIP in the years 2006-2008. Compared with the pre-NIP 2-year period, in 2009-2011, hospitalizations for RVGE were reduced by 76 % and outpatient clinic visits were reduced by 81 %. NVGE showed a slight decreasing trend and accounted for 34 % of all cases of GE seen in hospital in pursuance of RVGE having decreased to 26 % (down from 52 %). In cases admitted to the hospital ward, RV accounted for 28 % and NV accounted for 37 %.The impact of RV vaccination was reflected as a 57 % decrease in all hospital admissions and 62 % decrease in all outpatient clinic visits for GE of any cause. Conclusion: RV vaccination in NIP has led to a major reduction of hospital admissions and clinic visits due to RVGE, but has had no effect on NVGE. After 2 years of NIP, NV has become the leading cause of acute GE in children seen in hospital.