The latest study, published Tuesday online by the journal Clinical Infectious Diseases, is by a team including researchers at the National Institutes of Health. They analyzed blood samples from more than 24,000 people across the country, collected in the first three months of 2020 as part of a long-term study called “All Of Us” that seeks to track 1 million Americans over years to study health.
More evidence suggests COVID-19 was in US in December 2019, including 5 cases in Illinois
