Evidence from trials and programs
Research shows that financial incentives can raise vaccination rates among some groups, but effects are context-dependent. A randomized trial led by Marcos A. Campos-Mercade at the University of Gothenburg found that modest cash payments increased COVID-19 vaccine uptake in Sweden, demonstrating that guaranteed payments can change short-term behavior. Real-world policy experiments in the United States, such as state lotteries and one-time cash offers, yielded mixed results: some evaluations detected small increases while others found little measurable impact, indicating that program design matters and that population-level effects are not uniform.
Why incentives work — and why they sometimes don’t
Incentives address economic barriers that disproportionately affect low-income adults: lost wages, transportation costs, and childcare can make vaccination practically costly. Guaranteed cash or vouchers reduce those immediate opportunity costs and can be particularly motivating where the marginal utility of money is high. However, incentives do not directly resolve non-economic barriers such as mistrust of health systems, language barriers, legal status concerns, or limited clinic hours. In some communities, offering money can raise ethical and cultural questions about coercion or stigmatization, especially where historical abuses have undermined trust.
Consequences and practical considerations
When well targeted and combined with outreach, guaranteed payments and small subsidies tend to outperform large-probability-lottery models, because the latter rely on uncertain rewards that can fail to motivate those most constrained. Consequences include short-term increases in coverage and potential improvements in population health, but also trade-offs: budgets diverted to incentives may reduce funding for trusted community engagement, and poorly framed offers can deepen suspicion. Territorial differences matter—urban, rural, immigrant, and Indigenous communities respond differently depending on local trust in institutions, access logistics, and cultural norms.
Bottom line
Financial incentives can increase vaccination uptake among low-income adults, particularly when payments remove direct costs and are paired with accessible services and culturally competent outreach. They are not a panacea: effectiveness varies by design, context, and existing levels of trust, so policymakers should combine incentives with structural supports and community engagement to achieve sustained, equitable increases in vaccination.