ABSTRACT
Political polarization is growing rapidly in the United States and has been linked to politicized public health issues including vaccination. Political homogeneity among one's interpersonal relationships may predict polarization levels and partisan bias. In this study, we analyzed if political network structure predicted partisan beliefs about the COVID-19 vaccine, beliefs about vaccines in general, and COVID-19 vaccine uptake. Personal networks were measured by whom the respondent discussed "important matters" with to obtain a list of individuals who are close to the respondent. The number of associates listed who share the political identity or vaccine status with the respondent was calculated as a measure of homogeneity. We find that having more Republicans and unvaccinated individuals in one's network predicted lower vaccine confidence whereas having more Democrats and vaccinated individuals in one's network predicted higher vaccine confidence. Exploratory network analyses revealed that non-kin others are especially impactful on vaccine attitudes when those network connections are also Republican and unvaccinated.