The influence of information sources on intention changes to receive COVID-19 vaccination: A prospective cohort study in Japan

BACKGROUND: Before the COVID-19 vaccine became available, many Japanese people were undecided about whether or not to receive them. Their decisions were keys to achieving herd immunity. The impact of the type of information source on the COVID-19 vaccine uptake decision-making process remains unclear. We aimed to investigate the association between information source usage on COVID-19 and subsequent vaccine uptake status among those who have yet to decide whether to receive vaccines from non-prioritized people for vaccination. METHODS: Prospective cohort online self-administered surveys were conducted in February 2021 (T1), before the start of the mass vaccination program, and September–October 2021 (T2), when the vaccines were available to all citizens. The survey’s target population was registered monitors of an Internet research company. Participants who answered “I want to get vaccinated after waiting to see how it goes.” at T1 were eligible for analysis. The outcome variable was the COVID-19 vaccine uptake status in T2, and the predictors were 20 types of information sources, categorized based on people (family members, etc.), institutions (governments, etc.), or media (TV news, etc.). Adjusted odds ratio and 95% confidence intervals were estimated using logistic regression adjusted for possible confounders. RESULTS: The 5,139 respondents, mean age and standard deviation was 42.8 ± 12.5, 55.7% female, were eligible for analysis. 85.7% completed vaccination (including reserved/intended people) in T2. In the multivariate logistic analysis, odds ratios (95% confidence interval) for vaccine uptake were 1.49 (1.18–1.89) for workplaces/schools, 1.81 (1.33–2.47) for LINE, 0.69 (0.55–0.86) for Internet news and 0.62 (0.48–0.82) for video sharing sites. CONCLUSIONS: The type of information source usage played an important role in the decision to vaccinate against COVID-19. Although caution is needed in interpreting the results, obtaining information from workplaces/schools and LINE was influential in promoting immunization. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1265/ehpm.22-00266.