On Tuesday, George Stephanopoulos shared a health update following his coronavirus diagnosis. Stephanopoulos announced he tested positive for COVID-19, the respiratory illness caused by the virus, on Good Morning America last week. “Good news for me and my family. Last week I tested positive for COVID antibodies, confirming I cleared the virus after weeks without symptoms,” he tweeted. “I’ve also signed up for a clinical trial to donate my blood plasma and expect to make the donation in the coming weeks.” An antibody test, also known as a serological test, can help indicate whether a person has already built an...