Factors underlying parental decisions about combination childhood vaccinations including MMR: a systematic review.

Suboptimal childhood vaccination uptake results in disease outbreaks, and in developed countries is largely attributable to parental choice. To inform evidence-based interventions, we conducted a systematic review of factors underlying parental vaccination decisions. Thirty-one studies were reviewed. Outcomes and methods are disparate, which limits synthesis; however parents are consistently shown to act in line with their attitudes to combination childhood vaccinations. Vaccine-declining parents believe that vaccines are unsafe and ineffective and that the diseases they are given to prevent are mild and uncommon; they mistrust their health professionals, Government and officially-endorsed vaccine research but trust media and non-official information sources and resent perceived pressure to risk their own child's safety for public health benefit. Interventions should focus on detailed decision mechanisms including disease-related anticipated regret and perception of anecdotal information as statistically representative. Self-reported vaccine uptake, retrospective attitude assessment and unrepresentative samples limit the reliability of reviewed data - methodological improvements are required in this area.