[Vocabulary] Game changer

[Silverobama]

Hi,

What does the "game changer" mean in this sentence?

He said, “We know that treatment as prevention has been documented to reduce transmission by 96 percent. This is remarkable evidence of progress. We now know that if you’re on treatment not only will you live longer and healthier, but you’ll be 96 percent less likely to spread HIV to others. That’s a game changer.”

Source

 

[Rover_KE]

The treatment will change your life (and the lives of others).

Rover

 

[Silverobama]

Is it an idiom or a word-by-word phrase?

 

[Rover_KE]

It's a metaphor. We are not literally talking about a game.

 

[Silverobama]

So how to understand "game" in the sentence?

Thanks a lot

 

[SoothingDave]

game-changing - definition of game-changing by Macmillan Dictionary

It's an expression.