Dozens of studies examining the effects of vaccine mandates have been published over the last year. A pre-print review of this literature has found that requiring COVID-19 vaccination may carry significant costs, including a deepening distrust of public health authorities and greater vaccine hesitancy.
Research going back many years has shown that vaccine mandates tend to backfire. Forcing people to get shots they don't want often exacerbates their skepticism. Even if a mandate works in the short term, boosting uptake of a particular vaccine, its efficacy wanes as people look for ways to reassert their autonomy, usually by refusing to get the next shot they're told to get.
Anecdotal evidence gathered over the last year has confirmed the results of these earlier studies on mandatory vaccination, but research investigating the specific effects of COVID vaccine mandates is beginning to trickle in. The first major review of this literature was published on February 1. After surveying the relevant research from behavioral psychology, socioeconomics, and law, the authors, a team of public health and legal scholars, concluded
"... that current COVID-19 vaccine policies should be reevaluated in light of negative consequences that may outweigh benefits. Leveraging empowering strategies based on trust and public consultation represent a more sustainable approach for protecting those at highest risk of COVID-19 morbidity and mortality and the health and wellbeing of the public"
The paper points to the potentially severe costs of mandatory vaccination policies and further strengthens the case against requiring immunizations in most circumstances.  If policymakers and public health experts want to reduce opposition to vaccination and other infection-control measures in the future, they should reevaluate their affinity for mandates.
Stoking the flames of skepticism
The case for mandatory vaccination usually goes something like this: SARS-CoV-2 is a deadly virus; immunization blunts its harmful effects; therefore, everybody should be vaccinated, even if they have to be forced to do so. After all, I don't have "the Freedom to Kill You With My COVID," as President Biden put it last October.
Setting aside the observation that the approved vaccines don't seem to prevent transmission of Omicron very well, there's another problem with the case for mandates. The world isn't inhabited by automatons who can be ordered around, but humans with differing values and priorities. Failing to account for this diversity is a recipe for trouble.
Some people, for example, prize their autonomy over anything else. Others, meanwhile, feel that they have been mistreated by the government and therefore don't trust federal institutions to protect their health. Still, other individuals distrust pharmaceutical companies and believe their products are dangerous by default. There is, of course, overlap between these groups as well.
Whether or not any of these factions has correctly assessed the situation is irrelevant for now. The key issue is that they feel justified in their opposition—and will push back on attempts to force their compliance. Psychologists call this response “reactance,” the human tendency to do the opposite of what we're told to do. You're also undoubtedly familiar with this behavior if you're a parent. The authors pointed to very recent research documenting this effect during the pandemic:
"Literature reviewed by Drury et al. (2021) … found that COVID-19 compulsory vaccination would likely increase levels of anger, especially in those who are already mistrustful of authorities, and do little to persuade the already reluctant. Two experiments in Germany and the USA found that a new COVID-19 vaccine mandate would likely energize anti-vaccination activism, reduce compliance with other public health measures, and decrease acceptance to future voluntary influenza or varicella (chickenpox) vaccines."
They argued, citing evidence from the UK, France, and Denmark, that vaccine passports can actually decrease the likelihood that people who aren't fully immunized will get their remaining doses. Someone may object that France's passe sanitaire actually increased COVID vaccine uptake, but that's not as compelling as it seems. The reality is that France's passport scheme had a very small impact on vaccination among the most vulnerable segments of the population, and it may have run “the risk of politicizing vaccination further and reinforcing distrust of vaccines,” as the authors of a January 12 study in Nature put it.
The danger of cognitive dissonance
Reactance isn't the only phenomenon in play, however. Throughout the pandemic, people worldwide have been subjected to confusing, contradictory public health advice. Just a few months ago in the US, for instance, the CDC insisted that "the COVID-19 vaccines presently authorized in the United States offer protection against known emerging variants, including the Delta variant, particularly against hospitalization and death." The agency proffered this advice while flip-flopping on the necessity of masking in public and warning Americans about the risk of breakthrough infections.
The mixed signals were enough to irritate anybody, but the authors of the new paper explained that they also induced cognitive dissonance (a psychological stress precipitated by the perception of contradictory information) that vaccine skeptics may have used as justification to ignore anything the public health establishment said about immunization:
Cognitive dissonance may have been compounded by the changing rationale provided for vaccine policies and public perceptions that certain information is being actively censored or selectively presented … Initial communication that COVID-19 vaccines would prevent transmission to vaccinated people contributed to skepticism and confusion once onerous non- pharmaceutical interventions (NPIs) were reintroduced in countries with vaccine mandates or passports in late 2021
Stigma as a public health strategy
Once the COVID vaccines were authorized, it soon became acceptable to stigmatize anyone hesitant to get one. Politicians called out the unvaccinated in speeches, threatening their employment or ability to otherwise participate in society. At the same time, calls to “let them die” proliferated across social media; late-night TV personalities cracked joked along the same lines. As Jimmy Kimmel put it,
Vaccinated person having a heart attack? Yes, come right in. We'll take care of you. Unvaccinated guy who gobbled horse goo [ivermectin]? Rest in peace, wheezy.
Suffice it to say that none of this ghoulish rhetoric had a positive effect. We all know that stigmatizing people is a poor way to win friends and influence people; research published last year reached the same conclusion. “Leveraging stigma as a public health strategy, regardless of whether or not individuals are opposed to vaccines, is likely to be practically ineffective at promoting vaccine uptake,” the review authors wrote.
Let's follow the science
There's one point worth stressing as we wrap up: this information didn't come from a segment of Tucker Carlson's show or a Ron DeSantis press conference. These are the results of peer-reviewed papers and analyses from pro-vaccine public health experts at Johns Hopkins and Oxford, among other reputable institutions.  If advocates of mandatory vaccination are as keen to "follow the science" as they have said they are, these results should give us pause before we again try to implement forced immunizations. Let's give the review authors the last word:
"It is time for policy to regain a focus on non-coercive public health measures, including pro-social language and community leadership for vaccination, especially to protect high-risk groups. There are other options to address the pandemic and it is not too late to return to empowering, transparent, and community-informed policies based on equity and non-discrimination that many public health practitioners have been calling for since the outset."
 Some of the issues discussed in the paper—how mandates affect electoral politics, privacy rights, and enable discrimination under the law—are beyond the scope of this article, though they are still worth considering.
 Specifically, they write that "COVID-19 vaccines were developed in record time to meet an urgent public health need and ... have been estimated to have prevented millions of deaths, severe hospitalizations and long-term sequelae from SARS-CoV-2."