Understanding and predicting parental decisions about early childhood immunizations.

This research investigated the factors that influence decisions about immunizations. Women in the third trimester of pregnancy (N=195) rated their likelihood of immunizing their child; stated their reasons for and against immunizing; and rated their perceptions of the benefits and risks of immunization, feelings of responsibility, and anticipated regret if harm occurred. Immunization status was determined at follow-up. Stepwise regression analyses demonstrated that immunization decisions are strongly influenced by omission bias factors such as anticipated responsibility and regret variance (which explained more than 50% of variance). It is suggested that parents may benefit from antenatal decision aids that address omission bias and encourage them to assess benefits and risks of immunizations on the basis of scientific evidence.