Using the risk information seeking and processing model, this study examined how five personality traits—extraversion, neuroticism, conscientiousness, openness to experience, and agreeableness—influenced individuals’ information-seeking behaviors and vaccination intentions. An online survey was administered by a reputable polling company commissioned by this study. The survey employed age, education, gender, and income as distinct strata for sampling, which resulted in 1100 valid questionnaires.The following five conclusions were drawn from the data analysis: (1) Of the five personality traits, two—extraversion and conscientiousness—exhibited a notable impact on individuals' information-seeking behaviors and vaccination intentions. Individuals with the remaining three personality traits—neuroticism, agreeableness, and openness to experience—demonstrate either passive or no information-seeking behaviors on COVID-19. (2) Conscientiousness was the only personality trait linked to increased awareness of COVID-19 characteristics. Moreover, conscientious individuals were inclined to avoid depending on ISNs to seek COVID-19 information and developed vaccination intentions. In contrast, individuals high in agreeableness heavily depended on ISNs for COVID-19 information to initiate information-seeking behaviors. Meanwhile, individuals high in extraversion relied on two variables—affective responses and ISNs—to begin their information-seeking behaviors. (3) Respondents' perceptions of COVID-19 characteristics and their affective responses did not positively influence their perceived information insufficiency directly; instead, both needed to be mediated by ISNs to initiate their information-seeking behaviors. (4) In contrast to the two variables—perceived COVID-19 characteristics and affective responses—this study found that ISNs regarding COVID-19 played a more substantial role in shaping respondents' information-seeking behaviors and vaccination intentions. (5) Unexpectedly, openness to experience was found to have no impact on information-seeking behaviors during the COVID-19 pandemic.