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Volokh Conspiracy

Public Opinion Supports Covid Vaccine Challenge Trials

A recent study finds broad support for the idea in many countries, including the US.


Back in May, I outlined the moral case for using "challenge trials" to speed up the process of testing and deploy possible coronavirus vaccines. In a challenge trial, volunteers would be given the vaccine and then deliberately infected with the virus, to see if the vaccine gives them immunity.

As economist Alex Tabarrok explains, challenge trials could potentially make vaccines available months earlier than it would be otherwise. And if we can make vaccination happen even a few weeks sooner than would be the case for conventional trials, we can save many lives, and avoid large economic and social costs, as well.

A recent article by Berkeley political scientist David Broockman and several coauthors finds widespread public support for challenge trials in numerous countries, including the US. Here is the abstract (HT: Tyler Cowen]:

A vaccine for COVID-19 is urgently needed. Several vaccine trial designs may significantly accelerate vaccine testing and approval, but also increase risks to human subjects. Concerns about whether the public would see such designs as ethically acceptable represent an important roadblock to their implementation, and the World Health Organization has called for consulting the public regarding them. Here we present results from a pre-registered cross-national survey (n= 5; 920) of individuals in Australia, Canada, Hong Kong, New Zealand, South Africa, Singapore, the United Kingdom, and the United States. The survey asked respondents whether they would prefer scientists to conduct traditional trials or one of two accelerated designs: a challenge trial or a trial integrating a Phase II safety and immunogenicity trial into a larger Phase III efficacy trial. We find broad majorities prefer for scientists to conduct challenge trials (75%, 95% CI: 73-76%) and integrated trials (63%, 95% CI: 61-65%) over standard trials. Even as respondents acknowledged the risks, they perceived both accelerated trials as similarly ethical to standard trial designs, and large majorities characterized them as "probably" or "definitely ethical" (72%, 95% CI:70-73% for challenge trials; 77%, 95% CI 75-78% for integrated trials). This high support is consistent across every geography and demographic subgroup we examined, including people of diverging political orientations and vulnerable populations such as the elderly, essential workers, and racial and ethnic minorities. These findings bolster the case for these accelerated designs and can help assuage concerns that they would undermine public trust in vaccines.

I do not claim that such widespread public support proves that challenge trials are morally justified. As the author of Democracy and Political Ignorance, I recognize that public opinion on policy issues is often influenced by ignorance, partisan and ideological bias, and other dubious considerations. Thus, my moral justification for challenge trials doesn't depend on how popular they are.

That said, the popularity of challenge trials is potentially significant because it might alleviate politicians' and business leaders' fears that holding such trials would lead to a public backlash. If Broockman and his coauthors are correct, the vast majority of people are likely to support challenge trials, despite the possible risks.

One limitation of the study is that the authors did not ask respondents whether they approve of paying challenge trial volunteers, which I argue is also justified, but some may object to on "commodification" and "exploitation" grounds, similar to those raised against legalization of organ markets. But even if payment to participants is limited to compensation for time and expenses and free health care for any complications they might suffer, it is likely we can still attract a large number of volunteers. The impressive 1 Day Sooner website has already signed up over 38,000 challenge trail volunteers from around the world (that figure may grow even higher by the time you read this).

Covid vaccines are, of course, already being tested in the US and elsewhere. But the progress is impeded by the inherent slowness of the process, and in some cases by a shortage of volunteers from specific demographic categories. Challenge trials could help address both problems.

The faster the better. Time is money. And in this case it's literally a matter of life and death, as well.