5 years? He's never had any.
Go read up on him, well, anything not a fluff piece (he loved buying off the press), the man has always been this way.
While I wouldn't put it past him to fake it I think there's enough evidence to say he has it at this point. Of all times to get it, this would probably be the worst they could have picked. Besides this being a critical time for campaigning, which he needs to do, it's too late for a change of strategy on this and that doesn't even get into what happens if he dies or has to resign for health reasons.
Just wait, based on photos I saw of the events they were at (not to mention flying around in Air Force one together with no masks), I will be amazed if neither Bill Barr, Chris Christie or Mike Pence have it, Pence may already have it but they just haven't announced it for fear of how people will react (so say rumors). A bunch of the press caught it and White House staffers who initially made light of it are now in fear. There are signs it's actually worse than they're letting on, the White House med facility should be able to take care of it, they mostly lack a respirator, and the Pentagon is saying everything will be fine (why are they even involved?). Just the fact that he stayed overnight is a clue, the secret service doesn't like a Pres staying at a hospital, it's a health and a security risk, which is why White House is equipped like it is.
Also at meetings with those same people earlier in the week was an entire senate committee (who they now think may all now be infected), Lyndsey Graham and Mitch McConnell and frankly I'd keep an eye on Chris Wallace (the debate moderator) as well. Another event late this week had Trump schmoozing wealthy donors ($250k a person) and there was no safety protocols in place, this was mere hours before he tested positive. Oops. They waited 24 hours to notify these people, not that it matters, several of them said they refuse to self isolate regardless (thanks!).
Again, is it a surprise if they have it? They all acted like nothing was going on, shaking hands, hugging, sitting close...
Edit/update:
Trump says he plans to stay (and work) in the hospital for several days, this hasn't happened since Reagan was shot.