Pathways to COVID-19 vaccine initiation: The roles of medical mistrust, conspiracy beliefs, hesitancy, and confidence among black young adults.

Medical mistrust, stemming from historical and contemporary inequalities in healthcare, poses a major barrier to vaccination, particularly among Black communities in the southern U.S. While medical mistrust is known to influence vaccine uptake, the underlying psychological mechanisms, such as conspiracy beliefs and attitudinal factors like vaccine hesitancy and confidence, are not well understood. This cross-sectional analysis used baseline data from the Tough Talks-COVID randomized controlled trial (N = 360), conducted among Black young adults (ages 18-29) in Alabama, Georgia, and North Carolina between March and June 2023, who had not completed the primary COVID-19 vaccine series at screening. Participants completed validated measures of medical mistrust, vaccine-related conspiracy beliefs, vaccine hesitancy, vaccine confidence, and COVID-19 vaccine initiation (ever receipt of ≥1 dose at baseline). Serial mediation models specifying a theoretically informed ordering (medical mistrust, vaccine-related conspiracy beliefs, vaccine hesitancy or vaccine confidence, and COVID-19 vaccine initiation) were tested adjusting for age, sex, and state. Medical mistrust was significantly associated with lower odds of COVID-19 vaccine initiation (B = -0.63, AOR = 0.53, p < .001). Serial mediation analyses revealed two significant indirect associations: (1) Greater medical mistrust was associated with stronger endorsement of vaccine-related conspiracy beliefs, which were linked to increased vaccine hesitancy, resulting in lower vaccine initiation (B = -0.26, CI[-0.463, -0.127]); and (2) Greater medical mistrust was associated with stronger vaccine-related conspiracy beliefs, which were associated with reduced vaccine confidence; higher vaccine confidence was associated with higher vaccine initiation, yielding an overall negative indirect association (B = -0.35, CI[-0.591, -0.191]). Findings highlight critical psychological mechanisms through which medical mistrust may undermine COVID-19 vaccine initiation in under-vaccinated Black young adults. Addressing mistrust and countering conspiracy beliefs while strengthening vaccine confidence may support vaccine initiation efforts in Black communities.