U.S. population at increased risk of severe illness from COVID-19
Ezimamaka Ajufo, Shreya Rao, Ann Marie Návar, Ambarish Pandey, Colby Ayers, Amit Khera
Abstract
The U.S. Centers for Disease Control and Prevention (CDC) recognizes that older adults and individuals with certain medical conditions are at increased risk of severe COVID-19 infection. Understanding the proportion of the population at risk of severe infection, including among those with heart disease, could assist current vaccine strategy efforts. Using data from the 2015-2018 National Health and Nutrition Examination Survey (NHANES), we estimated the weighted prevalence of any of eight of eleven increased-risk conditions (including age ≥65) in U.S. adults aged ≥18 (N = 10,581) and extrapolated these results to a population of 233.8 million U.S. adults ≥18, and subgroups from the overall population defined by race/ethnicity, education, income and history of heart disease. An estimated 176.1 million individuals representing 75.4% of U.S. adults had at least one increased-risk condition, 40.3% ≥2 and, 18.5% ≥3 conditions. Approximately 129 million adults aged <65 (69.2%) were also estimated to be at increased-risk. Compared to Whites, similar proportions of Blacks in the overall population (78.0 vs. 75.6%, p>0.05) and Hispanics in the younger population (70.8 vs 68.4%) were estimated to be at increased-risk. Conversely, a greater proportion of individuals with lower education and income levels were estimated to be at increased-risk both in the overall and younger population. In addition, an estimated 6.2 million individuals (14.5%) had heart disease. Among these, virtually all had at least one additional CDC risk factor (97.9%) and most had ≥2 or ≥3 risk factors (83.8% and 58.5%, respectively). As vaccination strategies are being explored, these results demonstrate that >75% of adults in the U.S. would be considered at increased-risk for severe COVID-19 infection by CDC criteria. Risk factor prevalence alone may not adequately capture the totality of risk, particularly among Black and Hispanic racial/ethnic groups and those with heart disease.