We sought to identify barriers to COVID-19 vaccine uptake among persons who are socially vulnerable in light of the natural cycle of innovation diffusion. Widespread adoption of a health innovation requires a cadre of opinion leaders to build on successes experienced by early adopters. One type of opinion leader in healthcare are health mavens: members of a community who maintain up-to-date health knowledge and share their knowledge others. We surveyed 139 persons who are socially vulnerable regarding their COVID-19 vaccination intention, and evaluated their responses based on psychological traits captured by two scales: innovativeness and health mavenism. Health mavenism was not strongly correlated with COVID-19 vaccine intention. Health mavens often relied on their own healthcare providers (n = 46) and health agency websites (n = 42) for vaccine information. Those who relied on their faith leaders (n = 4) reported a lower likelihood of getting vaccinated (31.5% vs. 76.0%, p < .05). The observed lack of support by health mavens represents a critical barrier to COVID-19 vaccine uptake; targeting campaigns to health mavens may increase COVID-19 vaccine uptake in socially vulnerable communities.