BOSTON — The Vatican has rejected an appeal by parishioners who have occupied a Scituate church in protest since the Roman Catholic Archdiocese of Boston closed it eight years ago.

The decision announced Monday by the archdiocese is a blow to a protest at St. Frances X. Cabrini church that is, by far, the strongest remaining of several that arose after widespread church closings were announced by the archdiocese in 2004.

In the ruling, the Vatican upheld Cardinal Sean O’Malley’s decision to convert the Scituate church building to secular use — a step necessary before sale.

Jon Rogers, leader of the round-the-clock vigil in Scituate, said the decision was unjust, and parishioners will appeal to the Vatican’s high court.