The condition and Peter O'Mahony and Bundee Aki were two of the main worries following Ireland's 27-3 win against Scotland on Sunday morning.
Both players left the pitch to undergo HIA's with neither returning. Aki was replaced by Chris Farrell after 20 minutes and O'Mahony by Jack Conan after 27 minutes.
"They're both fine now, which is reassuring," Joe Schmidt told RTÉ following the game.
We'll have to wait and they'll have to go through the protocol of HIA 2 and HIA 3 to determine whether or not they've suffered a concussion.
For us, six days is the minimum to turnaround after a concussion. We'll just see how they are symptomatically.
Right here, right now, there's a bit of reassurance about those two.
Schmidt said Aki's injury could "potentially" cause problems at centre due to Robbie Henshaw also being injured.
"Less so with Pete," said the Ireland head coach.
"We've got Rhys [Ruddock] to come back in. At centre, Chris [Farrell] opened them up a few times. He was very big in the air for us. He's there and Garry Ringrose is there and Keith Earls has played there for us in the past and so has Jordan Larmour.
"We can mix and match a little bit. Right from the start, when I named the squad, versatility was one of the things I talked about. Inevitably, guys are going to have to be versatile at some stage."
After taking Ireland's first two kicks at goal, Johnny Sexton ceded responsibility to Conor Murray.
"He was able to kick," explained Schmidt.
"That was us being super-cautious because we got such a good start. We felt we could cover him up a little bit. We got him and Conor [Murray] off reasonably early. They were really big for us in the pivot area today with their kicking game and their game sense.
"They controlled things really well for us in that first half, got us through the first 15 minutes of the second half. I felt we were far enough in front and close enough to that last quarter that we could get them off and get ready for a six-day turnaround."
Picture credit: Sportsfile
