Overcoming COVID-19 Vaccination Resistance When Alternative Policies Affect the Dynamics of Conformism, Social Norms, and Crowding Out

"What is an effective vaccination policy to end the COVID-19 pandemic?"

Opposition to even voluntary COVID-19 vaccination has emerged in many countries. In many cases, those hesitating appear to be taking their cues from others. Based on an online survey conducted in Germany, this paper provides a model of policy effectiveness to explore the dynamics of vaccine resistance. The key ideas motivating the model are that voluntary citizen compliance is essential to policy success and that compliance preferences are possibly "crowded out" by enforcement policies or, on the other hand, enhanced due to conformism, as more other citizens comply. The panel data tracks intraindividual changes in trust in public institutions and vaccine acceptance, allowing inferences about causal effects.

The online panel of 2,653 Germans, surveyed by the Cluster of Excellence "The Politics of Inequality" at the University of Konstanz both in April/May and in October/November of 2020, allows the researchers to track the attitudes of the same individuals during the first and second lockdowns in Germany. The German government's explicit endorsement of voluntary vaccination regimes did not change over the course of the two waves of the survey. In both waves, respondents were asked: "If there is an approved vaccine against the coronavirus: To what extent would you agree to be inoculated yourself if: ... vaccination is strongly recommended by the government but remains voluntary? ... vaccination is made mandatory and checked by the government?" Answers were given on a five-point Likert scale. Notably, the questions ask about the respondent's attitude ("agree") toward vaccination and not whether a person would comply with a legally imposed and enforced vaccination policy. Moreover, the voluntary option in the survey has a strong normative content ("strongly recommended").

Those expressing full support for vaccinations if mandated fell from 44% to 28%. Support for enforced vaccinations in October/November 2020 was much more likely to be expressed by those who believed the pandemic was critical locally. This makes withdrawal of support for government-mandated vaccination particularly striking, given that between the two waves of the survey, the daily infection rate in Germany increased 15-fold. In contrast, for voluntary vaccinations, there was higher and undiminished support.

The research indicated that, the more that respondents trust public institutions, the more they agree to get vaccinated under both implementation (mandatory and voluntary) schemes. The study's indicator of an individual's trust in public institutions - termed "public trust" - is the average of their expressed general trust in the federal government and specific trust in its truthful information about COVID-19, as well as their trust in the state government, in science, and in media (which are all highly correlated).

The study revealed that public distrust undermines vaccine acceptance: The fall in support for enforced vaccination occurred disproportionately among those whose public trust declined between the two waves of the survey, suggesting that the association between trust and vaccine support may reflect a causal relationship. The distrust effect is substantial: A one-point drop in the public trust measure (ranging from 1 to 6.6) would account for 37% of the observed reduction in support for enforced vaccines between the two waves.

Furthermore, such distrust is associated with a belief that, if enforced, the vaccine compromises individual freedom. That is, the greater support for voluntary as opposed to enforced vaccinations is consistent with the idea that intrinsic or social motivations associated with getting vaccinated may be diminished by removing the vaccination decision from an individual's choice by implementing it as a government mandate. There are three mechanisms by which this might occur: (i) "psychological reactance" (intrinsic motivation being crowded out by explicit constraints); (ii) "moral disengagement" (explicit incentives or constraints framing the decision problem as one in which ethical convictions - e.g., altruism - are not salient); or (iii) distrust communicated by enforcement (signaling low expectations about citizens' behaviour).

Next, the researchers modeled how the willingness to be vaccinated may vary over time in response to the fraction of the population already vaccinated and whether vaccination has occurred voluntarily or not. A negative effect of enforcement on vaccine acceptance (of the magnitude observed in this panel or even considerably smaller) could result in a large increase in the numbers that would have to be vaccinated unwillingly in order to reach a herd-immunity target.

As the data suggest, citizens' preferences are not fixed but will be affected by the crowding-out effects not only of enforcement but also by conformism. The latter is defined here as the tendency of people to adopt some behaviour, belief, or other learned trait conditionally on others having adopted it. As reported here: "Conformism can have a positive effect on the diffusion of a novel vaccination even if initial acceptance by a population is modest. This is because those initially willing to be vaccinated may send a positive signal regarding their willingness to cooperate and their belief in the vaccine's safety and effectiveness. But complying with enforced vaccination sends a much weaker signal."

A key implication is that "The implementation of any policy as a legally enforced requirement or a morally framed recommendation signals to citizens the nature of the relationship in which they are engaged: hierarchical if enforced or, alternatively, as members of a community perhaps subject to a social contract if voluntary..."

The researchers provide some advice for policymakers:

• Mandating vaccination by law may have a substantial negative impact on voluntary compliance and may be unnecessary even if vaccine hesitancy is initially high.
• A viable anti-COVID-19 policy is to enhance public trust, possibly through greater transparency and accountability of politicians and medical professions.
• Convincing citizens that the vaccine is effective appears to be important in order to undermine antivaccine sentiments.
• Reporting the prevalence of those already or willing to be vaccinated may induce a cascade of others to abandon their vaccination hesitancy. Conversely, media attention to those refusing the vaccine could also generate a conformist cascade of vaccine resistance.

In conclusion, these findings "have broad policy applicability beyond COVID-19 to cases in which voluntary citizen compliance is essential because state capacities are limited and because effectiveness may depend on the ways that the policies themselves alter citizens' beliefs and preferences."