In ordinary circumstances, Catholics are obliged to participate in Mass on Sundays and other holy days of obligation.  This obligation is suspended in cases of moral or physical impossibility, and may also be dispensed for a just cause when it is for the spiritual good of the faithful.  In addition, the church also has the obligation to protect those who are most vulnerable and those who care for the sick.  The obligation to attend Sunday Mass, and for Confession, until further notice, is suspended.  Sunday remains a holy day, and Catholics should still observe the Lord's Day by making a "spiritual communion" while watching Mass online, on TV or radio.  You can pray the Liturgy of the Hours, the Rosary, make a good Act of Contrition and other devotions.