A cluster randomised controlled trial of a web based decision aid to support parents' decisions about their child's Measles Mumps and Rubella (MMR) vaccination.

OBJECTIVE: To evaluate the effectiveness of a web based decision aid versus a leaflet versus, usual practice in reducing parents' decisional conflict for the first dose MMR vaccination decision. The, impact on MMR vaccine uptake was also explored. DESIGN: Three-arm cluster randomised controlled trial. SETTING: Fifty GP practices in the north of, England. PARTICIPANTS: 220 first time parents making a first dose MMR decision. INTERVENTIONS: Web, based MMR decision aid plus usual practice, MMR leaflet plus usual practice versus usual practice only, (control). MAIN OUTCOME MEASURES: Decisional conflict was the primary outcome and used as the, measure of parents' levels of informed decision-making. MMR uptake was a secondary outcome. RESULTS: Decisional conflict decreased post-intervention for both intervention arms to a level where, parents could make an informed MMR decision (decision aid: effect estimate=1.09, 95% CI -1.36 to -0.82; information leaflet: effect estimate=-0.67, 95% CI -0.88 to -0.46). Trial arm was significantly, associated (p<0.001) with decisional conflict at post-intervention. Vaccination uptake was 100%, 91%, and 99% in the decision aid, leaflet and control arms, respectively (χ(2) (1, N=203)=8.69; p=0.017). Post-hoc tests revealed a statistically significant difference in uptake between the information leaflet, and the usual practice arms (p=0.04), and a near statistically significant difference between the, decision aid and leaflet arms (p=0.05). CONCLUSIONS: Parents' decisional conflict was reduced in both, the decision aid and leaflet arms. The decision aid also prompted parents to act upon that decision and, vaccinate their child. Achieving both outcomes is fundamental to the integration of immunisation, decision aids within routine practice. TRIAL REGISTRATION: ISRCTN72521372.