COVID-19 Vaccination Coverage and Intent Among Adults Aged 18–39 Years

United States, March-May 2021

Brittney N. Baack, MPH; Neetu Abad, PhD; David Yankey, PhD; Katherine E. Kahn, MPH; Hilda Razzaghi, PhD; Kathryn Brookmeyer, PhD; Jessica Kolis, MPH; Elisabeth Wilhelm, MA; Kimberly H. Nguyen, DrPH; James A. Singleton, PhD


Morbidity and Mortality Weekly Report. 2021;70(25):928-933. 

In This Article


During March–May 2021, nearly one fourth of adults aged 18–39 years were unsure about whether to receive a COVID-19 vaccine or were probably going to get vaccinated, and nearly one fourth reported that they would probably not or definitely not get vaccinated. Among adults aged 18–39 years, those who were younger, were non-Hispanic Black, had lower incomes and educational attainment, had no health insurance, and lived outside of metropolitan areas had the lowest reported vaccination rates and intent to get vaccinated.

The findings in this report indicate that trust in COVID-19 vaccines, particularly in their safety and effectiveness, was an important factor in the decision to get vaccinated among adults aged 18–39 years, especially for those who were unsure about or probably planning on getting vaccinated. Compared with those who were probably or definitely not planning to get vaccinated, this group was more concerned about getting COVID-19, indicating that information about vaccine safety and effectiveness might have influenced their decision to get vaccinated. This information might be a motivating factor if it were to come from trusted sources, such as health authorities, primary health care providers, and family and friends. In contrast, vaccine messages from employers, religious leaders, or social media might not be as effective. Adults aged 18–39 years who were unsure about getting vaccinated or probably going to get vaccinated reported that a desire to protect others and resume social activities were motivators to get vaccinated, suggesting that messages emphasizing that vaccination would allow them to resume social activities and encouraging vaccination for the greater good might be effective. Ensuring that vaccines are easily accessible, convenient, and available in places where young adults live and work could also improve vaccine acceptance and coverage.[9]

The findings in this report are subject to at least eight limitations. First, although panel recruitment methodology and data weighting were designed to produce nationally representative results, respondents might not be fully representative of the general U.S. adult population. Second, although data were weighted to account for differential nonresponse, low overall response rates might also affect sample representativeness. Third, because of small sample sizes for the age group 18–39 years within individual surveys, data were combined across multiple survey waves for this analysis, which might have minimized recent changes in vaccination coverage and intent status. Fourth, vaccination intent categories were combined in this analysis, which might have minimized distinctions between categories. However, a preliminary analysis of data from a CDC survey found that attitudes, perceptions, and behaviors were similar for each of the categories within a group. Fifth, state-specific vaccine eligibility varied during the data collection period, and some adults might not have been eligible during previous surveys, which might have affected vaccination coverage responses to questions related to attitudes, behaviors, and perceptions. Sixth, attitudes, behaviors, and perceptions might change quickly, and these results might not reflect current COVID-19 vaccine barriers and motivators. Seventh, results were designed to be national estimates, cannot be generalized at state or local levels, and did not include an examination of geographic differences. Finally, results might not be comparable to results from other national polls or surveys because of potential differences in survey methods, sample design, and framing of questions related to vaccination intent.

Achieving high vaccination coverage among adults aged 18–39 years is critical to protect this population from COVID-19 and to reduce community incidence. Increasing confidence in vaccine safety and effectiveness and emphasizing that vaccines are important for preventing the spread of COVID-19 to family and friends and resuming social activities might help increase coverage in this younger adult population, particularly among those who are unsure about whether to get vaccinated.[5]