Jews need to have faith in Christ like anyone else to be saved. Their covenant is intact in its fulfilled form, but they are not faithful to it by refusing to put their faith in Jesus Christ.
The People of God, which in Old Testament times was called “Israel” is now called “the Catholic Church.” It is no longer just for faithful Jews (that is, people of the Jewish race who have embraced Jesus and the fullness of truth) but membership has also been extended tofaithful Gentiles as well. Likewise, Jews who reject the gifts of God by refusing to embrace the Messiah are cut off from the people of God. The Second Vatican Council embraced this doctrine greatly throughout Lumen Gentium (it is why it uses the phrase “People of God”). It also explicitly calls the Church, the “new Israel.”
“Israel according to the flesh, which wandered as an exile in the desert, was already called the Church of God.(96) So likewise the new Israel which while living in this present age goes in search of a future and abiding city (97) is called the Church of Christ.(98)”