The article is about how there were test results included in the CDC's numbers that came from both viral and antibody tests, which most experts agreed was confusing. Viral tests try to determine current infection, whereas antibody tests are aimed at past infection. This error was identified, and as of early May, it was resolved, with CDC numbers reflecting only viral test results. A big part of the issue is that different states reported their numbers differently, and many of the states were reporting negative test results from viral and antibody tests as a single figure. The big issue here, though, is that this mistake would only make the outbreak look far less severe than it would otherwise.