Josephine van Dongen

1 General introduction 15 To reduce the risk of intussusception after vaccination, the current rotavirus vaccines should be administered early in life, preferably between six and nine weeks of age and no later than sixteen weeks of age for the first dose. Following vaccination with live-attenuated rotavirus, shedding of vaccine type in the feces fre- quently occurs. Studies have demonstrated that shedding develops in 50 to 95% of vaccinated infants. 75–77 In general, shedding of live-attenuated rotavirus vaccine strain is highest after the first dose.Theoretically there is a risk of transmission of vaccine type rotavirus and infection of other individuals. Disease due to a rotavirus vaccine type in healthy subjects has so far been described in one case repor t, which occurred after reassor tment of two vaccine types present in the pentavalent vaccine RotaTeq. 78 A study among premature infants receiving rotavirus vaccination at discharge showed that shedding did not lead to symptomatic transmission to household members. 79 In addition, the concentration of vaccine-derived shedding virus is much lower than of the vaccine itself and hygiene measures should prevent the risk of transmission. 80 The current generation rotavirus vaccinations are not considered to be an environmental risk. Implementation of rotavirus vaccination programs Since 2009, the World Health Organization (WHO) advises the implementation of rotavirus vaccination in all national immunization programs. 81 In the Netherlands rotavirus vaccination is currently not par t of the national immunization program, but has been under consideration for years. Vaccine decision making is organised as follows; the Dutch Health Council advises the ministry of Health about potential new vaccines for the national immunization program. The minister then decides on implementation of vaccinations. The national institute of Health and Environment executes the national immunization program. Vaccine counselling and delivery is organized via youth healthcare providers in well-baby clinics. In 2007 the Dutch Health Council stated the impor tance of rotavirus vaccination and that they would make an advise based on future cost-effectiveness analyses and more evidence on prevalent serotypes. 82,83 Nonetheless, in 2013 no advise was given as there was still discussion concerning cost-effectiveness and whether rotavirus disease would qualify as a notewor thy preventable disease given the gener- ally mild course of disease. 84 For infants with MRC, disease course can however be worse due to (complications of) rota- virus and five to six annual deaths were estimated in this par ticular group. Fur thermore, the results of a Dutch cost-effectiveness analysis indicated that a selective rotavirus vaccination strategy (targeting these medical risk infants exclusively) would be cost-effective and could reduce mor tality. 28 However, there were concerns about the feasibility of a selective strategy. In the Netherlands there was no experience with such a strategy and good quality effectiveness data for these high-risk infants were also lacking. For these reasons, in anticipation of a new Health Council advise, the RIVAR project started in 2014.