A systematic review analyzed 30 predominantly US studies with more than 8000 patients published between 1990 and 2012 (4 RCTs, 7 nonrandomized clinical trials, 13 before/after intervention trials, and 6 evaluation studies) to evaluate interventions that decreased parental vaccine refusal and hesitancy.1 Interventions included: change in state law, changes in state and school policies, and family-centered education initiatives.
Four studies that evaluated the impact of state laws concerning personal exemption (in addition to religious exemption) consistently found that total nonmedical exemption rates were higher in states that allowed personal exemptions. One nationwide survey found that total nonmedical exemption rates were 2.54 times higher (95% confidence interval [CI], 1.68-3.83) in states that allowed personal exemption than in states where only religious nonmedical exemption was allowed.
Fifteen studies evaluated the impact of educational initiatives on parental attitude towards vaccination; 8 of them reported statistically significant changes. None of the studies demonstrated a change in vaccination rates, however. Citing the generally low quality of the studies, the review authors concluded that they didn’t have convincing evidence that educational interventions reduced vaccine hesitancy.
Herd immunity is an iffy motivator
A systematic review analyzed 29 studies from western nations (17 qualitative and 12 quantitative, 4650 patients) regarding willingness to immunize children for the benefit of the community.2 Of the 17 qualitative studies, only 2 (164 patients) identified benefit to others as a motivating factor in parents’ decisions to immunize their children. In the 12 quantitative studies, a wide range of parents (1% to 60%) rated the concept of benefit to others as a reason for immunization. Overall, approximately one-third of parents listed herd immunity as a motivating reason. The authors concluded that the high heterogeneity of the studies made it unclear whether herd immunity was a motivating factor in childhood immunizations.
Multifaceted interventions, education, and tailored approaches may all work
A systematic review of international studies published between 2007 and 2013 investigated interventions to increase uptake of routinely recommended immunizations in groups with vaccine hesitancy and reduced use.3 Authors identified 189 articles (trial types and number of patients not given) that provided outcome measures.
Interventions that resulted in at least a 25% increase in vaccine uptake were primarily multifaceted, including elements of: targeting undervaccinated populations, improving access or convenience, educational initiatives, and mandates. Interventions that produced a greater than 20% increase in knowledge were generally educational interventions embedded in routine processes such as clinic visits.
The authors noted wide variation between studies in effect size, settings, and target populations. They concluded that interventions tailored to specific populations and concerns were likely to work best.