Parental financial incentives for increasing preschool vaccination uptake: systematic review

Financial incentives have been used to promote vaccination uptake but are not always viewed as acceptable. Quasimandatory policies, such as requiring vaccinations for school enrollment, are widely implemented in some countries. A systematic review was conducted to determine the effectiveness, acceptability, and economic costs and consequences of parental financial incentives and quasimandatory schemes for increasing the uptake of preschool vaccinations in high-income countries.

Electronic databases and gray literature were searched for randomized controlled trials, controlled before-and-after studies, and time series analyses examining the effectiveness of parental financial incentives and quasimandatory schemes, as well as any empirical studies exploring acceptability. All included studies were screened for information on economic costs and consequences. Two reviewers independently assessed studies for inclusion, extracted data, and assessed the quality of selected articles by using established instruments. Studies were synthesized in narrative reviews.

Four studies on the effectiveness and 6 on the acceptability of parental financial incentives and quasimandatory interventions met the inclusion criteria. Only 1 study reported on costs and consequences. Studies of effectiveness had low risk of bias but displayed substantial heterogeneity in terms of interventions and methods.

There was insufficient evidence to conclude whether these interventions were effective. Studies of acceptability suggested a preference, in settings where this already occurs, for incentives linking vaccinations to access to education. There was insufficient evidence to draw conclusions on economic costs and consequences.