Less than 10% of Americans had COVID by September, study finds

Large-scale seroprevalence studies conducted over the summer show that, through September, less than 1 in 10 of Americans had evidence of previous coronavirus infection, researchers from the Centers for Disease Control and Prevention (CDC) reported yesterday in JAMA Internal Medicine. In the nationwide seroprevalence survey, researchers from the CDC's COVID-19 Response Team tested blood serum samples from people in 50 states, the District of Columbia, and Puerto Rico during four periods from July through September, looking for the presence of detectable antibodies for SARS-CoV-2, (the virus that causes COVID-19.