World Rugby has issued a statement to help fans better understand the process of identifying and managing concussion in elite rugby.
Any player who displays clear signs of concussion during a match such as loss of consciousness, loss of balance and dazed etc., should be permanently removed from play and must not return to play before 12 days. A full list of these signs known as Criteria 1 can be found here.
The in-game Head Injury Assessment, known as the HIA 1 test, combines video review and off-field medical observation. Players may be removed from play (i.e. not return to the field) following this HIA test as a precaution and a replacement player used whilst the assessment take place. This test advises if a player should sit out the rest of the game as a precaution, it does not a confirm a concussion.
If the player passes the subsequent HIA 2 test which takes place after the match and HIA 3 test which takes place 36 hours after the game, the player does not have a confirmed concussion. In these circumstances, the player is available for the next match and is not required to undertake the return to play protocols. If a player does not pass either the HIA2 or HIA3 test then a concussion is diagnosed and the player will return according to recently updated protocols which will like see them miss the next match.
The Head Injury Assessment process only applies to elite rugby where there is an extremely high level of constant medical care. Such an environment is not possible at the community level and anyone who suspects a concussion at the community level should seek medical advice immediately as per World Rugby guidelines.