Shetler

Churches and sacred objects can of course be re-consecrated, but only if they lose their blessing by profanation, which does not indicate that the effects of their consecrations were only fallibly produced but rather that through some subsequent effect they were afterwards lost.
The Spanish Jesuits describe the efficacy of sacramentals as follows:
The efficacy of these sacramentals is not ex opere operato, but neither is it ex opere operantis, as if their efficacy were such as the good works of the faithful have. The efficacy of the sacramentals is derived from the fact that they are the petitions of the Church, which, since they are most acceptable to God, are efficacious in a special way; but they do not have their effect infallibly. Therefore the efficacy of the sacramentals is quasi ex opere operato, or ex opere operantis Ecclesiae.

- Joseph Shetler, “Some Contemporary Questions on Sacramentals Considered according to the Scholastic Theology of Their Mode of Efficacy.” (STL Thesis,Angelicum,2007), 18.