Josephine van Dongen

4 Rotavirus vaccine effectiveness 99 Table 1 . Comparison of characteristics between before-after cohor t participants Intention to treat (ITT) According to protocol (ATP) Pre-imple- mentation period: all infants N=631 $ Post-imple- mentation period: all infants N=851 $ p-value Pre-imple- mentation: willing to vaccinate N=496 Post-imple- mentation: vaccinated N=719 p-value Male sex 361 (57.2%) 456 (53.8%) 0.19 286 (57.7%) 381 (53.0%) 0.11 Multiple bir ths 158 (25.0%) 230 (27.1%) 0.37 115 (23.8%) 193 (26.8%) 0.15 Premature bir th (ges- tation < 37 weeks) 549 (87.6%) 753 (88.8%) 0.47 432 (87.8%) 635 (88.3%) 0.79 Gestation- al age in weeks + days among those premature (SD) 31+4 (3+1) 31+6 (2+6) 0.03 31+3 (3+1) 32+1 (2+5) <0.001 Figure 2 . Flowchar t of recruitment and cohor t groups. *Reasons for not approaching: 596 versus 663 discharged or referred (50.4% vs 53.9%), 201 versus 177 no Dutch speaking parent (17.0% vs 14.4%), 193 versus 96 unstable home situation (16.3% vs 7.8%), 82 versus 103 poor prognosis (6.9% vs 8.4%), 110 versus 190 other unspecified reason (9.3% vs 15.5%). Missing refers to missing information on whether infant was not approached or no consent was obtained. $82 missing information on willingness to vaccinate and 6 missing information on vaccination status. Abbreviations: ITT = intention to treat, ATP = according to protocol, AGE= acute gastroenteritis, n= number with characteristic.