Broad cross-national public support for accelerated COVID-19 vaccine trial designs

Abstract

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 ethical represent an important roadblock to their implementation; accordingly, both the World Health Organization and numerous scholars have called for consulting the public regarding them. We answered these calls by conducting a cross-national survey (n = 5920) in Australia, Canada, Hong Kong, New Zealand, South Africa, Singapore, the United Kingdom, and the United States. The survey explained key differences between traditional vaccine trials and two accelerated designs: a challenge trial or a trial integrating a Phase II safety and immunogenicity trial into a larger Phase III efficacy trial. Respondents' answers to comprehension questions indicate that they largely understood the key differences and ethical trade-offs between the designs from our descriptions. We asked respondents whether they would prefer scientists to conduct traditional trials or one of these two accelerated designs. We found broad majorities prefer for scientists to conduct challenge trials (75%) and integrated trials (63%) over standard trials. Even as respondents acknowledged the risks, they perceived both accelerated trials as similarly ethical to standard trial designs. This high support is consistent across every geography and demographic subgroup we examined, including vulnerable populations. These findings may help assuage some of the concerns surrounding accelerated designs.

Keywords: COVID-19; Challenge trials; Public opinion; Vaccine ethics.

Fig. 1

Example Stimulus, Study 1 (Study A is the Challenge Trial in this Example). Note: In order to communicate the details and differences between standard and challenge trials, participants in Study 1 were shown a table like the one above. The highlighted elements were randomized across possible values detailed in the Supplementary Materials. The highlights did not appear for respondents. We randomized these parameters given uncertainty about how particular vaccine trials might be conducted, to ensure our findings were not sensitive to any of these parameters. We did not allow participants to move on from the page describing the trial design until at least 60 seconds had gone by. See the Supplementary Materials for an example from Study 2. As we show in the Supplementary Materials (Tables S2 and S6), the vast majority of survey respondents were able to correctly comprehend the key differences between the designs.

Fig. 2

Broad Support for Challenge Trials and Integrated Trials That Accelerate COVID-19 Vaccine Development. Notes: The Figure shows the percent of respondents who preferred that scientists conduct each accelerated trial instead of a standard trial. Study 1 considered the use of a challenge trial in which participants are intentionally exposed to the virus instead of, in a standard trial, waiting for participants to be exposed to it in their daily lives. Study 2 considered the integration of smaller Phase II safety and immunogenicity trials into larger Phase III efficacy trials instead of, in a standard trial, waiting for the completion of a Phase II safety and immunogenicity trial before commencing a Phase III efficacy trial. The Figure shows the mean proportion of respondents who say they would prefer scientists to conduct each accelerated design for each study overall, by geography, and across various demographic subgroups. 95% confidence intervals surround the point estimates. Sample sizes shown are totals across both studies; respondents are approximately evenly split across the two studies. See Tables S3, S4, S7, and S8 for numerical values. * This Figure presents non-white respondents from Hong Kong only. There were an unanticipatedly large number of participants in Hong Kong who indicated they were white. The 2016 Hong Kong Census estimates that only 0.8% of the Hong Kong population identifies as white; we discuss this issue in further detail in the Supplementary Materials.

Fig. 3

Vast Majority of Survey Respondents Describe Both Accelerated Designs as Ethical.