ABSTRACT
INTRODUCTION: Focusing on subpopulations that express the intention to receive a COVID-19 vaccination but are unvaccinated may improve the yield of COVID-19 vaccination efforts. METHODS: A nationally representative sample of 789,658 U.S. adults aged ≥18 years participated in the National Immunization Survey Adult COVID Module from May 2021 to April 2022. The survey assessed respondents' COVID-19 vaccination status and intent by demographic characteristics (age, urbanicity, educational attainment, region, insurance, income, and race/ethnicity). This study compared composition and within-group estimates of those who responded that they definitely or probably will get vaccinated or are unsure (moveable middle) from the first and last month of data collection. RESULTS: Because vaccination uptake increased over the study period, the moveable middle declined among persons aged ≥18 years. Adults aged 18-39 years and suburban residents comprised most of the moveable middle in April 2022. Groups with the largest moveable middles in April 2022 included persons with no insurance (10%), those aged 18-29 years (8%), and those with incomes below poverty (8%), followed by non-Hispanic Native Hawaiian or other Pacific Islander (7%), non-Hispanic multiple or other race (6%), non-Hispanic American Indian or Alaska Native persons (6%), non-Hispanic Black or African American persons (6%), those with below high school education (6%), those with high school education (5%), and those aged 30-39 years (5%). CONCLUSIONS: A sizable percentage of adults open to receiving COVID-19 vaccination remain in several demographic groups. Emphasizing engagement of persons who are unvaccinated in some racial/ethnic groups, aged 18-39 years, without health insurance, or with lower income may reach more persons open to vaccination.