Objective: To determine the reasons that motivate parents to enrol or not enrol their child in a randomized, controlled vaccine trial.
Design: Cross-sectional survey.
Setting: Offices of primary care physicians in Dartmouth, Nova Scotia, and Montreal, Quebec.
Participants: At the 2 sites, parents of 2-month-old infants at their first immunization visit who had decided to enrol (221) or not enrol (208) their child in 2 randomized pertussis vaccine trials.
Outcome measures: Rates of enrolment in vaccine trials; attitudes about medical research; sources of information about pertussis.
Results: Enrolment rates were 68% and 43% at the 2 sites. All parents agreed to answer questions about their decision to enrol or not enrol their child. The most common concerns resulting in nonenrolment were extra immunization 54% (26/48) and blood procurement 42% (20/48). Parents who did enrol their children were motivated to participate by the desire to contribute to medical knowledge (77% [170/221]), the desire to help others (48% [106/221]) and by the participation of their family physician (54% [120/221]). The enrollees' major sources of information about pertussis was health professionals or study personnel rather than the media.
Conclusions: Altruistic reasons motivate parents' decision to enrol a child in a randomized, controlled vaccine trial. Nonparticipating parents seem most concerned about painful procedures in the study. Parents' decisions regarding participation do not appear to be affected by adverse media attention regarding the purported adverse sequelae of pertussis vaccines.