Biden covid case highlights confusing CDC guidance on ending isolation

Before President Joe Biden emerged from coronavirus isolation Wednesday, he made double-sure he was no longer contagious. He received negative tests Tuesday night and Wednesday morning. To test at all meant Biden was going above and beyond the guidance from the Centers for Disease Control and Prevention for exiting isolation. The CDC has built that guidance around a timeline - a prescribed minimum number of days of isolation - rather than the direct, personalized evidence of virus shedding that rapid antigen tests provide. But the usefulness of these tests was highlighted anew Saturday when Biden, who had taken the antiviral during his illness, tested positive again and returned to isolation in the White House residence.

More than 2 and one-half years into the pandemic, and with a highly contagious version of the virus circulating, the CDC guidelines for what to do when falling ill - and when to return to public life - continue to stoke as much confusion as clarity. That's a reflection of the changing nature of the virus, the inherent unpredictability of an infection, and the demands and expectations of work and home life. With new research showing that people are often infectious for more than five days, the CDC guidance has drawn criticism from some infectious-disease experts. The Biden protocol strikes many of them as the right way to go - because it's empirical evidence that a person isn't shedding virus. The CDC does not explicitly recommend a negative test to patients who want to resume activities. It describes such a test, which offers a direct if imperfect measure of contagiousness, as optional. The guidance states that a patient should isolate for at least five days. (Day 1 is the day after your symptoms manifest or your test was collected.) Patients who end isolation should continue to wear a well-fitting mask around others at home or in public through Day 10.