The CC teaches that Adam’s descendants contract a state, not an act. We’re not accountable for Adam’s sin but were nevertheless changed and affected by it. The change has been referred to as the “death of the soul”, a death that calls for a rebirth, a reawakening, a raising from the dead. Its chief characteristic is separation from God. We’ve lost the “knowledge of God”, the direct, personal, knowledge of Him, from birth. Jesus came to reconcile this situation, as the time became ripe in human history. “Now this is eternal life: that they know you, the only true God, and Jesus Christ, whom you have sent.” John 17:3
By everything He said and did Jesus came to reveal the Father so that we may know Him, in order to believe in and ultimately love Him with our whole heart, soul, mind, and strength. So that we may commune with Him as is the right and just order of things for man. This is what Adam failed to do, and this is what humans are still called to do with the help of time spent here in this very non-Edenic world, effectively separated from God where we can begin to develop a hunger and thirst for Him with the help of revelation and grace, and so turn back to Him like Prodigals back to their father. This is how we’re “born again” or “born from above”. This is how we’re justified, the chief effects of original sin overcome in us.