JMIR Publications

ABSTRACT

Background:

High COVID-19 vaccine uptake is crucial to containing the pandemic and reducing hospitalizations and deaths. Younger adults (aged 20-39) have demonstrated lower levels of vaccine uptake compared to older adults while being more likely to transmit the virus due to a higher number of social contacts. Consequently, this age group has been identified by public health authorities as a key target for vaccine uptake. Previous research has demonstrated that altruistic messaging and motivation is associated with vaccine acceptance. In this study, we evaluated the efficacy of a short, animated video that highlights altruistic reasons for COVID-19 vaccination to enhance vaccination intentions in unvaccinated Canadian younger adults.

Objective:

This study had two objectives: (1) to evaluate the within-group efficacy of an altruism-eliciting video intervention in increasing COVID-19 vaccination intentions amongst younger adults; and (2) to examine the video’s efficacy compared to a text-based intervention focused exclusively on non-vaccine related COVID-19 preventive health measures.

Methods:

Using a web-based survey in a pre-to-post, randomized control trial design, we recruited Canadians aged 20-39 who were not yet vaccinated against COVID-19 and randomized them in a 1:1 ratio to receive either the video intervention or an active text control. The video intervention was developed by our team in collaboration with a digital media company. The measurement of COVID-19 vaccination intentions before and after completing their assigned intervention was informed by the multi-stage Precaution Adoption Process Model. The McNemar’s Chi-square test was used to evaluate within-group changes of vaccine intentions. Exact tests of symmetry using pairwise McNemar tests were applied to evaluate changes in multi-staged intentions. Between-group vaccine intentions were assessed using the Pearson’s Chi-square test post intervention.

Results:

Within-group results for the video intervention arm showed that there was a significant change on intentions to receive the vaccine (χ^2(1) = 20.55, p < .001). The between-group difference in post-intervention intentions (χ^2(3) = 1.70, p = .637) was not significant. When administered the video intervention, we found that participants who had not thought about or were undecided about receiving a COVID-19 vaccine were more amenable to change than participants who had already decided not to vaccinate.

Conclusions:

While the video intervention was limited in its effect on those who had firmly decided not to vaccinate, our study demonstrates that prosocial and altruistic messages could increase COVID-19 vaccine uptake, especially when targeted to younger adults who are undecided or unengaged regarding vaccination. This might indicate that altruistic messaging provides a “push” for those who are tentative towards, or removed from, the decision to receive the vaccine. The results of our study could also be applied to more current COVID-19 vaccination Clinical Trial: This study was registered on ClinicalTrials.gov (NCT04960228).