Josephine van Dongen

3 Updated cost-effectiveness and risk-benefit analysis 53 Introduction In recent years, the Netherlands has seen an unexpected change in rotavirus epidemiology, while infant rotavirus vaccination coverage (the vaccine has been licensed since 2006) has remained below 1%. Annual epidemics were observed until 2013; thereafter, an alternating pattern of high- and low epidemic years emerged ( Fig. 1 ). During low endemic years, rotavirus detections in virological surveillance decreased by 58% (2014) and 52% (2016) compared to an average of the years before 2013, and a delayed star t of rotavirus seasons was observed 1, 2 . Similarly, general practice (GP) consultation rates for acute gastroenteritis (AGE) during the winter months in children under 5 years old were reduced 3 , and the prevalence of asymptomatic rotavirus observed in daycare attendees was significantly lower in 2014 (prevalence rate 0.6%) compared to 2011–2013 (prevalence rate 6.8–11.2%) 4 . Rotavirus detections and seasonal GP consultation rates during the alternating years 2015 and 2017 were comparable to pre-2014 numbers 3, 5 . Due to this changing epidemiology, the overall incidence of rotavirus disease in the Dutch pediatric population has reduced substantially. To our knowledge, a similar change in epidemic pattern has not been observed in any other European country without a national infant rotavirus vaccination program. Fig. 1 Weekly number of rotavirus detections in sentinel laboratory surveillance (for 2017 only up to week 40) Although the driving factors for this change in epidemic pattern are currently unknown, it has been suggested that, apar t from a declining bir th rate and temperature fluctuations, rotavirus dynamics in the Netherlands may also be influenced by vaccination policies in neighboring countries 6 . Universal rotavirus vaccination programs have been implemented in all three neighboring countries of the Netherlands (Belgium in 2006, Germany in 2013, the UK in 2013), with coverage varying between 78% and 94% 7-9 . Implementation in these countries was