Why do coronavirus symptoms linger for some survivors?

The FDA granting emergency use authorization for the new Johnson & Johnson single-shot vaccine is good news in the fight to stop the spread of COVID-19. But so-called “long-haulers” are still experiencing symptoms, like loss of taste and smell, long after they’ve tested negative. Doctors are working to understand why some symptoms persist and what the years ahead might look like for survivors. NBC’s Gabe Gutierrez has this week’s Sunday Focus.