"No player will return to play until day 7 after injury and any player's return must be approved by an independent concussion consultant," the international federation wrote in its statement.
"Players, including those with a history of concussion or who have been removed from a game with obvious symptoms of concussion, will be unable to play for a minimum of 12 days, likely missing their next competitive game," added the supreme organ of rugby.
The majority of players will therefore be affected by this 12-day limit.
The new regulations will take effect on July 1 and will prevent, as is currently the case, a player who has successfully passed the return to play protocol from playing again the following weekend.
The matches of the July tours, such as that of England in Australia or France in Japan, are affected by this change.
"This is not just a new protocol, it will be a new mindset for coaches and players," World Rugby chief medical officer Eanna Falvey said in the statement.
"World Rugby firmly believes that the scientific evidence supports our protocols, but we are continually reviewing and testing them to ensure they are suitable for modern play."
"We recognize that there are differences in concussion symptoms and history and this process allows us to further protect elite players by individualizing their rehabilitation," said Eanna Falvey.
The Progressive Rugby organization has been campaigning since February for an extension of the mandatory rest period for players after a concussion.
She felt that these new rules were not perfect but that they "will prevent most high-level players from being exposed to high and unnecessary risks".
World Rugby is also the target of complaints from many former players with degenerative brain disorders who blame it for not having done enough to prevent these risks.
© 2022 AFP