Adherence to Palivizumab Prophylaxis

The goal of this clinical trial is to analyze implications of two alternative nudge-interventions to increase adherence to palivizumab prophylaxis in children with congenital heart disease. The main questions investigators aim to answer are: * Are well-established cognitive biases effective in increasing patient families' adherence to the palivizumab prophylaxis program? * What are the factors that affect families' adherence to the prophylaxis program and whether and how the effects of interventions depend on these factors? To study these questions investigators planned to utilize four well-established cognitive biases in designing two alternative nudge-interventions and investigators measured the effectiveness of each nudge-intervention against a control group. Patients were randomly allocated to one control and two treatment groups. In the control group, investigators informed participants about the prophylaxis program and provided a schedule. Patients in the first treatment group were additionally called two days before appointments (status quo bias), and were asked to plan the appointment day (implementation intention). Patients in the second treatment group received biweekly messages informing them about the benefits of the program as well as the current adherence rate (availability bias and social norm).