To date, over 51 million cases of COVID-19 have been reported in the U.S. While experts are still learning about the virus, one thing is for certain—it affects everyone differently. In fact, some didn't even know they had COVID, until looking back at symptoms they've experienced. That said, there are specific signs that point to COVID and according to the Centers for Disease Control and Prevention , here's 18 signs that indicate you've had COVID and still have " Long COVID " symptoms. (Do not mistake this for having immunity; experts recommend you get vaccinated even after having a prior infection). Read on to discover 18 signs of a previous infection—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID . 1 Difficulty Breathing or Shortness of Breath The ZOE COVID Study reports, "Shortness of breath usually occurs a week after initial infection. It's associated with having a mor