Before the war, Claire and Winter would eat dinner at several high-end restaurants. One such time was in Charlestown, where Claire and Winter dined with Arthur Black. After a waiter accidentally got Black's drink order wrong, Black fatally stabbed the waiter.
After this, Winter again wanted to take Claire out to dinner - this time at the Cornerstone Grille, where he assured Claire that Black would be on his best behavior.
Before the war started, Winter became aware of the coming nuclear armageddon. In order to survive and one day return to Boston, he underwent radiation treatment that turned him into a ghoul. He sent a holotape to Claire, asking her to join him in his bunker before the bombs fell, and to prepare herself for Eddie's change in appearance. However, it is not known if Claire made it to the bunker, as she is not present when the Sole Survivor and Nick Valentine confront Winter.
Claire Pozinski is mentioned only in Fallout 4.