The CDC surveyed U.S. adults (≥18 years) assessing vaccination intent (very likely to receive vaccination), vaccination nonintent (not likely to receive vaccination), and vaccine perceptions in September (n=3,541) and December (n=2,033) of 2020. Nonintent in September 2020 was highest among non-Hispanic Black adults (56%), followed by adults without health insurance (49%), adults with a high school education or less (47%), adults with an income of less than 35,000 (44%), adults aged 18 to 49 (40%) and 50 to 64 (42%), women (42%), and adults in the southern region of the U.S. (41%). When comparing responses from December to September, vaccination intent increased from 39% to 49% and vaccination nonintent decreased from 38% to 32%. During this same period, vaccination intent among elderly (≥65 years) increased from 49% to 66%, that among essential workers increased from 37% to 46%, and that among adults with underlying medical conditions under the age of 65 increased from 37% to 42%. Common reasons for vaccination nonintent included concern for vaccine side effects and safety, the speed at which the vaccine was developed, and intentions to wait and observe longer term effects of vaccine and its safety. Based on these findings, the authors suggest the need to address vaccination nonintent to ensure vaccination coverage for all populations.