St. Casimir is a patron of Poland and Lithuania.

Though a youth, you bore the burden of lung disease in purity and faith. Stand by the victims and families of this scourge of influenza, and strengthen their faith and love of Our Lord by your example. We beg you to add your prayers to ours for all of them, especially (N.) who struggles with this illness this day. Strengthen their trust in God, lend them ease in their suffering, and return them speedily to good health.
We implore the intercession of Our Lady of Sorrows at the altars in heaven. May the the graces of the Holy Spirit be sent to (N.) in this time of need.
'Hymn of St. Casimir'