While it is essential for Catholics, the obligation to attend can be dispensed, and the obligation has been dispensed at this time. This is stated in the Code of Canon Law which offers universal rulings for Catholics, and the Code has not changed since St John Paul II’s papacy. It states in canon 1247:
On Sundays and other holy days of obligation, the faithful are obliged to participate in the Mass. … If participation in the eucharistic celebration becomes impossible because of the absence of a sacred minister or for another grave cause, it is strongly recommended that the faithful take part in a liturgy of the word if such a liturgy is celebrated in a parish church or other sacred place according to the prescripts of the diocesan bishop or that they devote themselves to prayer for a suitable time alone, as a family, or, as the occasion permits, in groups of families.
In the Catechism of the Catholic Church, paragraph 2181, it further states:
The Sunday Eucharist is the foundation and confirmation of all Christian practice. For this reason the faithful are obliged to participate in the Eucharist on days of obligation, unless excused for a serious reason (for example, illness, the care of infants) or dispensed by their own pastor.