An estimate predicts that many more Americans may have had COVID-19 than originally thought.

The National Institutes of Health analyzed blood samples from more than 8,000 people never diagnosed with the virus.

Close to 5% of those people had virus antibodies.

Based on those findings, researchers estimate nearly 17 million people had undiagnosed cases of COVID-19 by mid-July 2020.

Those people were asymptomatic, never noticed symptoms and were never diagnosed.

To put it in context, the NIH says for every diagnosed COVID-19 case in the pandemic's first few months, they estimate there were nearly five undiagnosed cases.