14 Nor can it be asserted that the Redemption by Christ was on this account lessened, as if it did not extend to the whole race of Adam: and therefore something taken away from the office and dignity of the Divine Redeemer. For if we carefully and thoroughly consider the matter, we easily perceive that Christ the Lord in a certain most perfect manner really redeemed His mother, since it was by virtue of His merits that she was preserved by God immune from all stain of original sin. Wherefore, the infinite dignity of Jesus Christ and His office of universal redemption is not diminished nor lowered by this tenet of doctrine, rather it is greatly increased.
Source: Fulgens Corona (Vatican.va)