Pope Francis is still critically ill as he battles double pneumonia, but his condition has shown a "slight improvement", the Vatican said on Monday.

Francis was also given blood transfusions, according to the Vatican, after blood tests revealed he was suffering from thrombocytopenia, meaning the platelet count in his blood was too low, a condition the doctors said is associated with anemia. Infections and medical treatment may lower platelet count.

Several Filipinos in Vatican City joined the vigil and prayed the holy rosary at the St. Peter's Basilica on Monday night for the recovery of Pope Francis, whose condition remains critical as he battles pneumonia in both lungs.