Adults 20 to 49 years old may have kindled 72.2% of US COVID-19 resurgences starting in late summer 2020, with those 35 to 49 especially contributing, a study published yesterday in Science suggests.A team led by researchers from Imperial College London analyzed age-specific cell phone mobility data of more than 10 million Americans and linked them to age-specific COVID-19 death data starting on Mar 15, 2020.Data from 42 US states, Washington, DC, and New York City showed that the number of visits to places such as supermarkets and restaurants began to rebound across all age-groups in August after a significant initial reduction due to public health interventions such as lockdowns in the spring.