They must proceed even if a bishop or priest celebrates them in a church of empty pews. 

"By the mandate of the supreme pontiff for the year 2020 only," the congregation issued guidelines March 20 for celebrating the Triduum and Easter liturgies without the presence of the faithful.

"Easter is at the heart of the entire liturgical year and is not simply one feast among others. The Easter triduum is celebrated over the arc of three days, which is preceded by Lent and crowned by Pentecost and, therefore, cannot be transferred to another time," said the "Decree in the Time of COVID-19."

The decree was signed by Cardinal Robert Sarah, prefect of the congregation, and by Archbishop Arthur Roche, secretary.

 A sole  exception is being made for the chrism Mass because the chrism Mass is not formally part of the Triduum. Therefore a bishop can decide to postpone its celebration. 

Usually the Mass is celebrated during Holy Week and includes a gathering of all the priests of the diocese to renew their priestly promises. During the Mass, the oils — the chrism — used in the sacraments are blessed by a bishop and distributed to the priests to take to their parishes.

But all other Holy week and Easter week liturgies must continue, the decree said. 

In places where public Masses have been canceled, bishops, in agreement with their bishops' conference, still must ensure that the liturgies are celebrated in the cathedral and in parish churches. The faithful should be advised of the times for the celebrations, so that they can pray at home at the same time.

"Live — not recorded — televisual or internet broadcasts are helpful," the decree said.

On Holy Thursday, the Mass of the Lord's Supper should be celebrated in the cathedral and in parish churches even if the faithful can't be present, it said.

 "The faculty to celebrate this Mass in a suitable place, without the people, is granted in an exceptional manner to all priests" this year.

"The washing of feet, which is already optional, is to be omitted" when there are no faithful present, it said. The traditional procession with the Blessed Sacrament at the end of the Mass also is omitted, and the Eucharist is placed directly in the tabernacle.

If there is any way to do so, the decree said, the Liturgy of the Lord's Passion should be celebrated and, among the formal prayers of petition, there should be "a special intention for the sick, the dead, for those who feel lost or dismayed."

For the celebration of the Easter Vigil without the faithful present, it said, the preparation and lighting of the fire is omitted, but the Easter candle is still lit and the "Exsultet" Easter proclamation is sung or recited.

Processions and other expressions of popular piety that are traditional around the world during Holy Week may be transferred to another date, the decree said. It suggested, for example, Sept. 14-15 in connection with the feast of the Exaltation of the Holy Cross.