COVID-19 vaccine uptake among individuals with Down syndrome in the Unites States

Introduction: Individuals with Down syndrome are at increased risk for severe disease from acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, making them a priority group for COVID-19 vaccination. Data on vaccine uptake and factors associated with vaccination are needed to inform strategies to improve uptake in this vulnerable population. Objective: To evaluate COVID-19 vaccine uptake and identify factors associated with vaccination among individuals with Down syndrome. Methods: The population included individuals with Down syndrome born during 1995–2021 and enrolled in the Tennessee Medicaid Program during the COVID-19 pandemic. We limited the study population to individuals who sought care at the Vanderbilt University Medical Center at least once between six months after their initial eligibility for the COVID-19 vaccine and October 1, 2024. Date and type of COVID-19 vaccine receipt were ascertained from the Tennessee Immunization Information System. Demographic and clinical characteristics associated with COVID-19 vaccine uptake and completion of the primary series were analyzed using multivariable logistic regression. Results: Among 438 individuals with Down syndrome, 95 (22%), 88 (20%), 187 (43%), and 68 (16%) first became eligible for COVID-19 vaccine at age 16+, 12–15, 5–11, and 6 months–4 years of age, respectively. Overall, 152 (35%) received at least one dose of the COVID-19 vaccine; of these, 138 (91%) completed the primary series. Younger age and lack of influenza vaccination history—either never or during the pandemic—were strongly associated with a reduced likelihood of receiving COVID-19 vaccine or completing the primary series. Conclusions: Only one-third of individuals with Down syndrome received any COVID-19 vaccine, indicating low uptake in this high-risk population. Readily available information on individuals' age and influenza vaccination history may help identify individuals at increased risk of remaining unvaccinated, thereby informing targeted strategies to improve coverage and reduce COVID-19–related morbidity.