人間行動学：報奨金を導入してもCOVID-19ワクチンプログラムは弱体化しない

Paying people to get vaccinated against COVID-19 does not lead to negative behavioural consequences, a Nature study reports. This finding may have implications for policy-makers who may be considering using financial incentives to spur behavioural change.

Financial incentives are used to catalyse behaviour change in many situations, such as encouraging people to give blood or participate in clinical trials. The practice can trigger initial behaviour change, but some scientists and policy-makers caution against the use of financial incentives because of the longer-term, unintended consequences they may cause. They express concerns that, for example, the practice can erode prosocial motivations, diminish perceived safety and trust, and cause people to reduce healthy behaviours once the payments stop. However, it is difficult to measure the unintended consequences of financial incentives.

In a study involving more than 5,000 people in Sweden, Florian Schneider, Pol Campos-Mercade, Armando Meier and colleagues show that offering to pay people to take a first dose of a COVID-19 vaccine did not affect the timing or likelihood of them taking a second or third dose that is payment-free. In addition, they found no negative effect on their sense of civic responsibility, trust in vaccination providers, or perceptions about the safety and efficacy of vaccinations.

In a complementary study of more than 3,000 participants, the same team also found that informing US residents about the existence of state incentive programmes for COVID-19 vaccination had no negative consequences on the willingness of participants to take a further vaccine dose, trust in the state government, safety and efficacy perceptions of vaccines, or intentions to donate blood or to receive a flu shot. They conclude that modest financial incentives for vaccinations can be used without concerns about unintended consequences.