A plenary indulgence is available today, but almost no one in the United States will be able to get this indulgence.
You see, in order for the faithful to obtain this plenary, your church or cathedral has to be having some kind of liturgical celebration (Mass, Liturgy of the Word, or something like it) and you have to attend it.
The plenary is available only for those who participate in the celebration of the world-wide observance.
If no parish near you is celebrating the World Day of the Sick, you can't get the plenary.
This problem doesn't just exist for this day - indult #5 in the Handbook of Indulgences states:
A plenary indulgence is granted to the faithful who, on days universally designated to foster certain religious intentions (e.g., the promotion of priestly and religious vocations, the pastoral care of the sick and infirm, strengthening the profession of faith in young people, and assisting others to lead a holy life, etc.), piously assist at celebrations of this kind; however, those who pray for these same intentions may gain a partial indulgence. [emphasis in the original].There are several similar celebrations of the universal Church scattered throughout the year.
But that's the problem with this particular indult - it requires your pastor to know about (and care about) the days enough to put them on his calendar.
The Church establishes days of plenary indulgences and prayers with plenary indulgences in order to encourage us to participate in these days and in these prayers. It's her way of enticing us to live a liturgical life in conformance with Christ's vision for us.
But these and other indulgences aren't just an encouragement to parishioners to participate in the life of the Church, it's also an encouragement to priests and to bishops to live the life of Faith.
Unfortunately, very few priests realize that they are supposed to be doing this.
Most priests don't even know an indulgence is available today, and even if they did, many wouldn't care because they think indulgences are old-fashioned.
So, for want of a good, knowledgeable priest, an opportunity for an indulgence is lost...
In that respect, in the midst of the universal celebration, it is a day of sadness for all of us who are not able to participate as the Church intends us to.