Booster COVID-19 Vaccinations Among Persons Aged ≥5 Years and Second Booster COVID-19 Vaccinations Among Persons Aged ≥50 Years

United States, August 13, 2021-August 5, 2022

Hannah E. Fast; Bhavini Patel Murthy; Elizabeth Zell; Lu Meng; Neil Murthy; Ryan Saelee; Peng-jun Lu; Yoonjae Kang; Lauren Shaw; Lynn Gibbs-Scharf; LaTreace Harris


Morbidity and Mortality Weekly Report. 2022;71(35):1121-1125. 

In This Article


By August 5, 2022, approximately one half of the eligible population aged ≥5 years had received a COVID-19 vaccine booster dose, representing approximately one third (34.0%) of the U.S. population aged ≥5 years. Booster and second booster dose vaccination coverage rates were lowest among the youngest age groups; males; Black, Hispanic, and multiracial persons; residents of rural counties; and Janssen primary series recipients. Some similarities existed between booster dose coverage and primary series coverage trends as of August 21, 2022, with children, adolescents, younger adults aged 18–24 years, males, and Black persons being underrepresented among fully vaccinated persons.[5]

Booster dose coverage was highest among adults aged ≥65 years (69.5%), with smaller coverage differences across sex, race and ethnicity, and urban-rural classification compared with that in adults aged 18–64 years. Among age groups, the lowest booster dose coverage was among children aged 5–11 years (15.6%), followed by that among adolescents aged 12–17 years (33.4%). Children aged 5–11 years were recommended to receive a booster dose most recently, which might partially explain the low coverage in this group. Racial and ethnic disparities in booster dose coverage were largest (≥26 percentage points) among persons aged 12–39 years. Understanding the factors contributing to low booster and second booster dose coverage among Black, Hispanic, and multiracial populations, and designing interventions to address these factors, is crucial to ensuring equitable access to COVID-19 vaccination.

Booster and second booster dose coverage rates among Janssen primary series recipients were lower than those among mRNA vaccine recipients. One possible reason for this is the Janssen 1-dose primary series might have been preferred by persons less likely to receive multiple doses, such as transient populations (e.g., persons experiencing homelessness), persons with limited access to health care, and persons with needle aversion. Booster and second booster dose coverage was lower among residents of rural counties than that among urban residents; lower COVID-19 vaccine acceptance has been observed in rural areas, and rural residents might also experience more barriers to accessing health care than do urban residents.[6] Persons living in rural areas were previously found to be less likely to engage in COVID-19 preventive behaviors such as mask wearing,[7] which would likely increase the potential benefit provided by a booster dose in this population.

The findings in this report are subject to at least five limitations. First, COVID-19 vaccine booster dose recommendations were released during a 10-month period, and some populations had less time than others to receive a booster dose. Further, changes in COVID-19 variant predominance and case prevalence during this period likely affected booster and second booster dose acceptance among different populations. Second, misclassification of vaccination status might have occurred if linkage among vaccination records in jurisdiction-specific data systems was not possible, if, for example, persons received doses in different jurisdictions. Third, eligibility was determined by age at primary series completion, and a small number of persons who met the minimum eligible age requirement after primary series completion might have been excluded. Fourth, a small proportion of booster and second booster doses might have been misclassified because information on immunocompromise status was not available to identify immunocompromised persons who might have received an additional primary series dose. In addition, misclassification might have occurred due to the definitions for booster and second booster doses, which were designed to include doses administered to immunocompromised persons. However, after receipt of a primary series, approximately 99.0% of persons who received 1 subsequent dose received this dose after the minimum recommended interval for a booster dose; 99.6% of persons who received 2 subsequent doses received the second postprimary series dose after the minimum recommended interval for a second booster dose.§§§ Finally, race or ethnicity was unknown, unable to be reported, or invalid for approximately one quarter of the population, which could bias results. In May 2022, the National Immunization Survey Adult COVID Module (NIS-ACM) found no substantial racial and ethnic disparities among fully vaccinated adults;[8] however, disparities across race and ethnicity were present in booster dose coverage based on NIS-ACM.

All fully vaccinated eligible persons aged ≥5 years are recommended to receive a COVID-19 booster vaccine dose, and certain populations, including adults aged ≥50 years, are recommended to receive a second booster dose when eligible.[4] Booster doses increase the primary series vaccine effectiveness and strengthen the immune response in children, adolescents, and adults.[1–3] Health care providers can educate and encourage all persons to receive a booster dose when they are eligible. Focused interventions should be developed and implemented to improve access to COVID-19 vaccines and ensure the effectiveness of public health communication and outreach to populations with low coverage, which might reduce health disparities.

§§§Calculations of the interval between primary series completion and postprimary series doses were available for 91.8% of booster dose recipients and 94.5% of second booster dose recipients (excluding data received via direct data submission). In these calculations, the minimum recommended interval for a booster dose was defined as 5 months between primary series completion and administration of the first postprimary dose; the minimum recommended interval for a second booster dose was defined as 4 months between administration of the first postprimary series dose and the second postprimary series dose.