Josephine van Dongen

7 Evaluation of implementing a targeted rotavirus vaccine program 161 Background Immunization in childhood has been found a highly (cost-)effective preventive measure 1 . However successful introduction of new vaccines is dependent upon multiple factors 2 . Requirements for successful implementation of new vaccines are structured organization of the immunization program, raising awareness and providing adequate information to parents, favorable vaccine characteristics, and a feasible implementation strategy. Specifically for childhood immunization, parental conceptions influence the willingness to receive vaccination and therefore vaccination coverage 3–5 . In addition, the attitude and perceptions of health care providers (HCP) towards vaccination have been identified as impor tant determinants for implementation success 6–8 . Vaccination coverage is a key performance indicator to evaluate vaccine strategy and implementation policy. As of 2020, at least 98 countries have implemented rotavirus vaccination in their National Immunization Program (NIP) 9 . Globally licensed rotavirus vaccines are Rotarix (GSK, Belgium) and RotaTeq (Merck and Co, USA). They both have a high efficacy against severe rotavirus gastroenteritis ranging from 80 to 100% in high-income countries 10–14 . The two vaccines are generally well-tolerated. In the Netherlands, the health council advised, in 2007, against universal rotavirus vaccination, due to insufficient evidence on a specific risk group for vaccination and rotavirus genotype distribution 15 . Because it was demonstrated that infants with medical risk conditions (MRC) had increased disease burden 16 , a targeted vaccination strategy was piloted for infants with MRC only.This Risk-group Infant Vaccination Against Rotavirus (RIVAR) project star ted in 2014. For program execution, pediatric secondary and ter tiary care facilities were made responsible, instead of well-baby clinics that offer all routine childhood vaccines of the NIP. The main objectives of the RIVAR project were: 1) to determine vaccine effectiveness of rotavirus vaccination among infants with MRC and 2) to assess the feasibility of implementing a targeted rotavirus vaccine program in secondary and ter tiary hospitals in the Netherlands.The second aim of the RIVAR project is described in this implementation study. Methods RIVAR project and intervention A full description of the project is published at www.trialregister.nl (NTR5361) 17 and vaccine effectiveness is described elsewhere ( chapter 4 ). In brief, rotavirus vaccination was implemented in thir teen Dutch hospitals with a Neonatal Intensive Care Unit (NICU) or post-Intensive Care (IC) ward.This intervention was added to standard care for premature infants (gestational age (GA) below 36 weeks), infants with a low bir thweight (LBW) less than 2500 grams and/or infants with severe congenital pathology (for a list of conditions, see chapter 4 ). In order to be eligible for rotavirus vaccination, infants should receive in- or out-patient care in the par ticipating hospitals between six and four teen weeks of age, corresponding with the time window for the first dose of rotavirus vaccine administration. Rotarix, the human rotavirus vaccine (HRV) was