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. 2024 Oct 18;58(11):768-777.
doi: 10.1093/abm/kaae053.

Predictors of Change in Vaccination Decisions Among the Vaccine Hesitant: Examining the Roles of Age and Intolerance of Uncertainty

Julia G Halilova  1 , Samuel Fynes-Clinton  2 , Donna Rose Addis  2   3   4 , R Shayna Rosenbaum  1   2
Affiliations

Predictors of Change in Vaccination Decisions Among the Vaccine Hesitant: Examining the Roles of Age and Intolerance of Uncertainty

Julia G Halilova et al. Ann Behav Med. .

Abstract

Background: Vaccine hesitancy and resistance pose significant threats to controlling pandemics and preventing infectious diseases. In a group of individuals unvaccinated against the disease caused by the SARS-CoV-2 coronavirus (COVID-19), we investigated how age, intolerance of uncertainty (IU), and their interaction affected the likelihood of having changed one's vaccination decision a year later. We hypothesized that higher IU would increase the likelihood of becoming vaccinated, particularly among individuals of younger age. We predicted that this effect would remain significant, even after controlling for delay discounting and trust in science.

Purpose: The goal of this research was to understand the factors influencing changes in vaccination decisions among the vaccine hesitant.

Methods: In a larger longitudinal study, ~7,500 participants from Prolific.co completed demographic and vaccination status questions, a delay discounting task, and the Intolerance of Uncertainty Scale in June-August 2021. Approximately 3,200 participants completed a follow-up survey in July-August 2022, answering questions about vaccination status, reasons for vaccination decision, and trust in science. We analyzed data from 251 participants who initially had no intention of getting vaccinated and completed the follow-up survey; 38% reported becoming vaccinated in the intervening year.

Results: Data were analyzed using multilevel logistic regression. Over and above other factors related to vaccination decisions (delay discounting, trust in science), younger participants were more likely to change their decision and become vaccinated a year later, especially if they had higher IU, confirming our predictions. Primary reasons for becoming vaccinated were necessity and seeking protection against the virus.

Conclusions: These findings highlight the complex interplay between age, uncertainty, and vaccination decisions, and inform health policies by suggesting the need for tailoring interventions to specific concerns in different age groups.

Keywords: COVID-19; Intolerance of uncertainty; Public health measures; Vaccination; Vaccine hesitancy.

Plain language summary

Vaccine hesitancy and resistance pose significant threats to controlling pandemics and preventing infectious diseases. It is important to understand the factors that influence whether or not unvaccinated individuals change their mind and get vaccinated. We investigated how age and one’s intolerance of uncertainty predicted the likelihood of changing one’s mind about getting a COVID-19 vaccination in a group of 251 unvaccinated participants. In mid-2021, these individuals indicated they had no intention to get vaccinated; by mid-2022, 38% of them reported that they had been vaccinated. Over and above other factors known to be related to vaccination decisions (delay discounting and trust in science), we found that younger participants were more likely to have changed their minds and become vaccinated a year later, especially if they were less tolerant of uncertainty. Of the reasons provided by participants for having been vaccinated, necessity and seeking protection against the virus were the most common. These findings highlight the complex interplay between age, uncertainty, and vaccination decisions. Importantly, these findings will inform health policies, suggesting the need for tailoring interventions to specific concerns in different age groups.

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Figures

Fig. 1.
Fig. 1.
The likelihood of being vaccinated (0 = unvaccinated and 1 = vaccinated) at Time 2, a year after reporting no intention to get vaccinated, plotted by age and total score on the Intolerance of Uncertainty Scale at Time 1. The plot indicates that younger age (shown in lighter shades) is associated with greater likelihood of change in vaccination status a year later in individuals with higher intolerance of uncertainty.
See this image and copyright information in PMC

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