After initial declines, in mid-2020 a resurgence in transmission of novel coronavirus disease (COVID-19) occurred in the United States and Europe. As efforts to control COVID-19 disease are reintensified, understanding the age demographics driving transmission and how these affect the loosening of interventions is crucial. We analyze aggregated, age-specific mobility trends from more than 10 million individuals in the United States and link these mechanistically to age-specific COVID-19 mortality data. We estimate that as of October 2020, individuals aged 20 to 49 are the only age groups sustaining resurgent SARS-CoV-2 transmission with reproduction numbers well above one and that at least 65 of 100 COVID-19 infections originate from individuals aged 20 to 49 in the United States. Targeting interventions—including transmission-blocking vaccines—to adults aged 20 to 49 is an important consideration in halting resurgent epidemics and preventing COVID-19–attributable deaths.

在最初的下降之后，2020 年中期，新型冠状病毒病 (COVID-19) 的传播在美国和欧洲出现复苏。随着控制 COVID-19 疾病的努力不断加强，了解推动传播的年龄人口统计数据以及这些数据如何影响放松干预措施至关重要。我们分析了美国超过 1000 万人的汇总、特定年龄的流动趋势，并将这些趋势与特定年龄的 COVID-19 死亡率数据机械地联系起来。我们估计，截至 2020 年 10 月，20 至 49 岁的个体是唯一维持 SARS-CoV-2 传播复苏且繁殖数远高于 1 的年龄组，并且 100 例 COVID-19 感染中至少有 65 例来自 20 至 49 岁的个体在美国。针对 20 至 49 岁成年人的干预措施（包括阻断传播疫苗）是阻止流行病死灰复燃和预防因 COVID-19 导致的死亡的一个重要考虑因素。