I'm not confident that any rule changes will have a meaningful impact. It's thought that it isn't just collisions to the head that cause a problem, but all tackles. This is because your brain gets damaged when it moves around in your skull, and this will happen every time your velocity suddenly changes e.g. when being tackled to the ground. This is also the reason that headguards/scrumcaps aren't effective in cutting down on head injuries.

What can be done to protect the players is limiting the number of contact training sessions they can attend, and also limiting the number of games a season each player is allowed to play.

Another option could be to seriously limit the number of substitutes each team is allowed to make, as this will mean the players will have to be fitter and therefore not as big, and hopefully this will reduce the impact each tackle will have. However Rugby League is also having to deal with head injuries and that game requires a lot more fitness than Rugby Union.

There are almost constant rule changes around the tackle laws, the breakdown and de-powering the scrum to reduce the amount of potential head trauma, but the professional era it's like an arms race. Even padding and head-gear, players seem to hit with even more force. And, like the article says, a lot of the concussions happen during the training sessions which is way more than the average amateur player would experience. It's still relatively soon to see the longer-term effects; the early batch of professionals from the mid/late 90s will soon be entering their 60s and I expect there will be more research papers..

IIRC there are results around brain damage in association football as well, mostly due to players heading the ball.

Guess nobody has dared suggest prohibiting head playing in association football. Would be interesting to see how the game would change if such a rule would be enacted.

You could hypothetically go to something like touch rugby. But I don't know how you'd recreate some of the more unique features of rugby union, like contested scrums, rucks, and mauls. The game would probably look more like touch rugby league.

The rules of American football were changed in response to the 1905 season when 19 college players died. Instead of banning the sport completely, they started allowing forward passes. Which completely changed the game and made it safer.

Ultimately it’s a game of large, athletic people smashing into one another. Short of playing touch rugby and eliminating scrums, it’ll never be safe.

But then it’s not rugby anymore

Removing the tackle component would be the only real way to solve the brain damage problem.

I don't think they'll do that within the next 20 years, however.

There is not a singular risk. In rugby some risks come from intentional foul play or accidents (high tackles, disguised hits on static players players at rucks and mauls, scrum collapses, etc.) Others come from the constant, somewhat controlled impacts that exist in normal play. These can expose the tackler to the impact versus the individual being tackled.

Any discussion on this topic needs to recognise how the game of rugby union has changed. It rapidly went from amateur to professional, but took some time for the current level of power and fitness to develop. You had powerhouses like Lomu in the 90s, but from the early-2000s you have legions of Ma'a Nonu level players. Safety protocols seem to be pushed down to the junior game more readily than the adult professional game. Much influence has come from rugby league which arguably has popularised particular styles of play that hadn't been used in union.

There is much more that could be written about the historical changes, but it has made a big difference to safety while culturally making it harder to implement changes. Big tackles become what many viewers want to see in the game and this perpetuates both a style of tackling and bulking up that didn't exist before. Line speed is monitored closely and everything to improve this results bigger players moving more quickly which anecdotally results in more serious impacts. Authorities know it, but reducing it makes the game less exciting for TV audiences and there is less money to go around. It's a vicious cycle.

There are clear and obvious changes which can be tested in the game, but pushing these through takes a very long time. A concern some have expressed is around impact/tactical substitutions (https://www.theroar.com.au/2021/08/14/grossly-negligent-lion...). Adding a bunch of fresh players in soccer later in the game is common. The thinking carried over to rugby. It was attractive because you had chubbies like me at the front of the scrum who could perform higher over 40 minutes than the full 80 minutes. When you are adding huge Nonu-types into a game with tiring players then problems can occur. I can't imagine that changes will happen here rapidly.

The junior game becomes an easy place to push changes. The argument is made that children are being protected, but then the changes don't bubble up. Encouraging low tackling under a certain age is good, but tactics need to come along with these rules. Head-on tackles can go higher head-on because you are trying to hold the player up or in place versus taking them down and possibly allowing them a few feet past you to touch the ball down for a try. It's all interlinked.

In summary: yes, but it's up to the leaders to drive changes top down at all levels and accept that they may lose some revenue.

(I played rugby all through school from 1992 to 1999 in Ireland and have followed local global play since. For all the sides of Nonu see https://www.youtube.com/watch?v=EoVpAjSN6Nc and then https://www.youtube.com/watch?v=DdEKqoOdhM0 - but, many other could be substituted in his place.)