Daily counts by age between 1998 and 2007 were extracted from the database. The ratio of the number of reported cases to the number of symptomatic cases in the population was assumed to be 1 in 35, based on figures from a study in England and Wales looking at under-ascertainment within rotavirus surveillance data [26]. Berkeley Madonna gives the root mean square deviation (RMSD)

between the data and the best fitting model. The deviation is the root mean square of the differences between individual data points in the dataset and the corresponding points in the model. There were 29200 (number of days x number of age groups) data points in the HPA rotavirus surveillance dataset used. We initially investigated the effects of a two-dose rotavirus mass vaccination programme with doses given www.selleckchem.com/products/CAL-101.html at two and four months of age [8]. Initial assumptions were that the full vaccine course conferred a protective effect against infection and disease similar to that of a primary natural infection. Studies have shown that vaccine efficacy is comparable in breastfed infants, compared to non-breastfed infants [27], so we assumed vaccinated infants can be successfully immunized prior to waning of maternal antibodies. We assumed that 96% of individuals receiving the full two doses were successfully immunized to a natural primary

infection. This figure was consistent

with the proportion of individuals who seroconverted VE-821 cell line following two doses of Rotarix in clinical trials [28]. Thus, 96% of individuals would be successfully immunized against a primary rotavirus infection with two doses of the vaccine and therefore bypass the first infected compartment to enter the second susceptible or recovered compartments. The proportion entering these compartments were equivalent to those entering these compartments after a natural primary infection. Using a method similar to that used by Pitzer et al. [29], this gives a vaccine efficacy after two doses of 36.5% (=0.96 × (1 − 0.62)) against infection and 64.3% (=0.96 × (1 − (0.62 × 0.25/0.47))) against any rotavirus gastroenteritis, an estimate Adenosine similar to the 72% vaccine efficacy against any rotavirus gastroenteritis of two doses of Rotarix vaccine in a phase III European clinical trial [30]. We explored a variety of vaccine coverage levels. The long-term relative effects of direct and indirect (herd immunity) protection of the vaccine were determined. The direct effect of vaccination on the incidence of rotavirus gastroenteritis was estimated as 1 − 0.643 × vaccine coverage. This method assumes all individuals receiving the vaccine have protection from birth. Clinical trials have demonstrated a protective effect of the vaccine after a single dose.