Financial incentives for vaccination do not have negative unintended consequences

Effectiveness of financial incentives on influenza vaccination among older adults in China: a randomized clinical trial

OBJECTIVES

To investigate the short-term and long-term effectiveness of different levels of financial incentives on increasing the willingness to vaccinate and vaccine uptake.

METHODS

A randomized controlled trial was conducted to investigate the effectiveness of financial incentives of three groups with monetary incentives (CNY 20, CNY 40, and CNY 60; 1 CNY = 0.13 EUR) vs. a control group-CNY 0-on influenza vaccine uptake among 720 older adults (≥60 years) in Beijing, China. The primary outcome was vaccine uptake, and the secondary outcomes were intention to vaccinate and length of time to immunization.

RESULTS

Financial incentive significantly promoted higher intention to influenza vaccination (120/178 [67.42%] vs. 442/542 [81.55%]; Relative Risk [RR], 1.21; 95% CI, 1.02-1.42) and higher vaccination participation (74/178 [41.57%] vs. 316/542 [58.30%]; RR, 1.39; 95% CI, 1.10-1.75). CNY 60 had the largest impact on the intention to vaccinate (15.00% vs. 13.48% and 13.90%) and vaccination uptake (19.42% vs. 14.05% and 16.67%) compared with CNY 20 and CNY 40. Time to vaccination was significantly lower among participants receiving incentives than those without ([37.21 days; 95% CI, 34.33-39.99] vs. [48.27 days; 95% CI, 43.47-53.07]; Hazard Ratio [HR] 1.57, 95% CI 1.22-2.03). We found no long-term influence of financial incentives on vaccination decisions in the following year (217/542, 40.04% vs. 65/178, 36.52%; RR 1.08, 95% CI 0.82-1.42).

DISCUSSION

Our study suggests that modest financial incentives will boost short-term influenza vaccination rates and shorten the length of time to immunization in China. No one single-time financial incentive had a long-term effect on future vaccination behaviours or helped establish regular vaccination behaviours.

An experimental test of whether financial incentives constitute undue inducement in decision-making

Around the world, laws limit the incentives that can be paid for transactions such as human research participation, egg donation or gestational surrogacy. A key reason is concerns about 'undue inducement'-the influential but empirically untested hypothesis that incentives can cause harm by distorting individual decision-making. Here I present two experiments (n = 671 and n = 406), including one based on a highly visceral transaction (eating insects). Incentives caused biased information search-participants offered a higher incentive to comply more often sought encouragement to do so. However, I demonstrate theoretically that such behaviour does not prove that incentives have harmful effects; it is consistent with Bayesian rationality. Empirically, although a substantial minority of participants made bad decisions, incentives did not magnify them in a way that would suggest allowing a transaction but capping incentives. Under the conditions of this experiment, there was no evidence that higher incentives could undermine welfare for transactions that are permissible at low incentives.

A survey of state and local practices encouraging pediatric COVID-19 vaccination of children ages 6 months through 11 years

OBJECTIVE

This report highlights state and local practices for optimizing the pediatric COVID-19 vaccination program for children ages 6 months through 11 years.

METHODS

State and local practices designed to optimize pediatric COVID-19 vaccine uptake were identified from a range of sources, including immunization program, CDC, and partner staff; and media stories or program descriptions identified via online searches.

RESULTS

A range of practices were identified across different categories: provider-focused practices, school-based practices, jurisdiction or health department-based activities, community-focused practices involving partners, use of vaccination incentives, and Medicaid-related practices.

CONCLUSIONS

Immunization programs and stakeholders implemented a variety of practices to meet the challenge of the pediatric COVID-19 vaccination program. The key findings may serve to inform not only the current pediatric COVID-19 vaccination program, but also future outbreak response work and routine immunization activities.

The causal effect of a health treatment on beliefs, stated preferences and memories

The paper estimates the causal effect of a health treatment on patients' beliefs, preferences and memories about the treatment. It exploits a natural experiment which occurred in the United Kingdom during the COVID-19 vaccination campaign. UK residents could choose to opt into the vaccination program, but not which vaccine they received. The assignment to a vaccine offered little objective information for learning about its qualities, but triggered strong psychological demand for reassuring beliefs. We surveyed a sample of UK residents about their beliefs on the different COVID-19 vaccines before and after receiving their jab. Before vaccination, individuals exhibit similar prior beliefs and stated preferences about the different vaccines. After vaccination, however, they update their beliefs overly optimistically about the safety and effectiveness of the vaccine they received, state that they would have chosen it if they could, and have distorted memories about their past beliefs. These results cannot be explained by conventional experience effects. At the aggregated level, they show that random assignment to a health treatment predicts a polarization of opinions about its quality. At the individual level, these findings provide evidence in line with the predictions of motivated beliefs and over-inference from weak signals in a real-world health setting.

Policy makers believe money motivates more than it does

To motivate contributions to public goods, should policy makers employ financial incentives like taxes, fines, subsidies, and rewards? While these are widely considered as the classic policy approach, a substantial academic literature suggests the impact of financial incentives is not always positive; they can sometimes fail or even backfire. To test whether policy makers are overly bullish about financial incentives, we asked county heads, mayors, and municipal government representatives of medium-to-large towns in Germany to predict the effects of a financial incentive on COVID-19 vaccination, and tested the exact same incentive in a field experiment involving all 41,548 inhabitants (clustered in 10,032 addresses) of the German town of Ravensburg. Whereas policy makers overwhelmingly predict that the financial incentive will increase vaccination-by 15.3 percentage points on average-the same financial incentive yielded a precisely estimated null effect on vaccination. We discuss when financial incentives are most likely to fail, and conclude that it is critical to educate policy makers on the potential pitfalls of employing financial incentives to promote contributions to public goods.

Motivating vaccination with financial incentives

Governments and organizations often offer cash payments for vaccination. How effective are such payments? A literature review shows that incentives usually increase vaccination, especially for nonhesitant populations and when using guaranteed payments. Concerns about negative unintended consequences are unsupported. We also discuss open questions and avenues for future research.

Financial incentives for COVID-19 vaccines in a rural low-resource setting: a cluster-randomized trial

We implemented a clustered randomized controlled trial with 6,963 residents in six rural Ghana districts to estimate the causal impact of financial incentives on coronavirus disease 2019 (COVID-19) vaccination uptake. Villages randomly received one of four video treatment arms: a placebo, a standard health message, a high cash incentive (60 Ghana cedis) and a low cash incentive (20 Ghana cedis). For the first co-primary outcome-COVID-19 vaccination intentions-non-vaccinated participants assigned to the cash incentive treatments had an average rate of 81% (1,733 of 2,168) compared to 71% (1,895 of 2,669) for those in the placebo treatment arm. For the other co-primary outcome of self-reported vaccinations 2 months after the initial intervention, the average rate for participants in the cash treatment was 3.5% higher than for participants in the placebo treatment (95% confidence interval (CI): 0.001, 6.9; P = 0.045): 40% (602 of 1,486) versus 36.3% (672 of 1,850). We also verified vaccination status of participants: in the cash treatment arm, 36.6% (355 of 1,058) of verified participants had at least one dose of the COVID-19 vaccine compared to 30.3% (439 of 1,544) for those in the placebo-a difference of 6.3% (95% CI: 2.4, 10.2; P = 0.001). For the intention and the vaccination outcomes, the low cash incentive (20 Ghana cedis) had a larger positive effect on COVID-19 vaccine uptake than the high cash incentive (60 Ghana cedis). Trial identifier: AEARCTR-0008775 .

Incentivizing free riders improves collective intelligence in social dilemmas

Collective intelligence challenges are often entangled with collective action problems. For example, voting, rating, and social innovation are collective intelligence tasks that require costly individual contributions. As a result, members of a group often free ride on the information contributed by intrinsically motivated people. Are intrinsically motivated agents the best participants in collective decisions? We embedded a collective intelligence task in a large-scale, virtual world public good game and found that participants who joined the information system but were reluctant to contribute to the public good (free riders) provided more accurate evaluations, whereas participants who rated frequently underperformed. Testing the underlying mechanism revealed that a negative rating bias in free riders is associated with higher accuracy. Importantly, incentivizing evaluations amplifies the relative influence of participants who tend to free ride without altering the (higher) quality of their evaluations, thereby improving collective intelligence. These results suggest that many of the currently available information systems, which strongly select for intrinsically motivated participants, underperform and that collective intelligence can benefit from incentivizing free riding members to engage. More generally, enhancing the diversity of contributor motivations can improve collective intelligence in settings that are entangled with collective action problems.

Cognitive ability, health policy, and the dynamics of COVID-19 vaccination

We examine the relationship between cognitive ability and prompt COVID-19 vaccination using individual-level data on more than 700,000 individuals in Sweden. We find a strong positive association between cognitive ability and swift vaccination, which remains even after controlling for confounding variables with a twin-design. The results suggest that the complexity of the vaccination decision may make it difficult for individuals with lower cognitive abilities to understand the benefits of vaccination. Consistent with this, we show that simplifying the vaccination decision through pre-booked vaccination appointments alleviates almost all of the inequality in vaccination behavior.

Behavioral market design

When it comes to behavioral change, economic design and behavioral science are complements, not substitutes. Chater & Loewenstein give examples from policy design. In this commentary, I use examples, often from my own research, to show how behavioral insights inform the design of the rules that govern market transactions.

Fear of COVID-19 disease and vaccination as predictors of vaccination status

Vaccination rates are still insufficient to prevent the spread of COVID-19, so immunity must be increased among the population in order to reduce the virus' spread and the associated medical and psychosocial effects. Although previous work has identified various factors associated with a low willingness to get vaccinated, the role of emotions such as fear of vaccination (FVAC) or fear of COVID-19 (FCOV), vaccination as a subjective norm (SN), psychological factors like general control beliefs (CB) or psychological resilience, and their interaction have been investigated less intensively. We used data from three cross-sectional waves of the German Panel COSMO (November 2021, N = 1010; February 2022, N = 1026; March 2022, N = 1031) and multiple logistic regression analyses to test whether vaccination rates are moderated by those factors. After controlling for covariates (age, sex, confidence in own intuition, optimism, well-being), we found that CB was no significant predictor of vaccination status. Higher FCOV and higher ratings in SN, however, were associated with an increased likelihood of being vaccinated. In contrast, higher FVAC was associated with a decreased likelihood of being vaccinated. Psychological resilience did not consistently moderate the associations between fear and vaccination status.

Nationwide health, socio-economic and genetic predictors of COVID-19 vaccination status in Finland

Understanding factors associated with COVID-19 vaccination can highlight issues in public health systems. Using machine learning, we considered the effects of 2,890 health, socio-economic and demographic factors in the entire Finnish population aged 30-80 and genome-wide information from 273,765 individuals. The strongest predictors of vaccination status were labour income and medication purchase history. Mental health conditions and having unvaccinated first-degree relatives were associated with reduced vaccination. A prediction model combining all predictors achieved good discrimination (area under the receiver operating characteristic curve, 0.801; 95% confidence interval, 0.799-0.803). The 1% of individuals with the highest predicted risk of not vaccinating had an observed vaccination rate of 18.8%, compared with 90.3% in the study population. We identified eight genetic loci associated with vaccination uptake and derived a polygenic score, which was a weak predictor in an independent subset. Our results suggest that individuals at higher risk of suffering the worst consequences of COVID-19 are also less likely to vaccinate.