Use of financial incentives to increase adult vaccination coverage: A narrative review of lessons learned from COVID-19 and other adult vaccination efforts

To encourage COVID-19 vaccination, governments have offered a wide range of incentives to their populations ranging from cash to cows. Often these programs were rolled out at scale before assessing potential effectiveness. To inform future policy, we conducted a narrative review to understand the evidence base informing these programs and the extent to which they are effective. While we found evidence on cash transfers increasing both the coverage and intention to be vaccinated for COVID-19 and other adult vaccines, improvements in coverage were limited. With mixed evidence, lottery programs did not appear to have a consistent meaningful impact on vaccination for COVID-19, and no evidence was identified on the positive effects of other non-cash incentives for COVID-19 or other adult vaccines. We conclude that the impact of cash transfers in incentivizing adult vaccination is marginal and their effectiveness in addressing vaccine hesitancy remains inconclusive.