Herd immunity after two years of the universal mass vaccination program against rotavirus gastroenteritis in Austria.

Austria was the first country in Europe implementing a universal mass vaccination program against rotavirus gastroenteritis (RV-GE) for all infants nationwide. Epidemiological data from a hospital based surveillance system show that incidence rates of children hospitalized with RV-GE decreased in 2009 compared to 2008 and compared to the prevaccination period 2001-2005. Decreasing hospitalization-rates from RV-GE were observed in children of all age groups, even in those not eligible for vaccination according to their age, suggesting herd immunity induced by universal mass vaccination against RV-GE. In 2009 the disease burden was highest in children below three months of age stressing the importance of the early start of the immunization course.