That BBC report says the diseases were transmitted when patients accepted the blood clotting fraction "Factor VIII":
BBC: They needed regular treatment with a clotting agent Factor VIII, which is made from donated blood.
JW's can't claim they were protected from this danger because it is a blood fraction, not one of the four banned components.
*** w00 6/15 p. 30 Questions From Readers ***
For example, clotting factor VIII has been given to hemophiliacs, who bleed easily. Or if someone is exposed to certain diseases, doctors might prescribe injections of gamma globulin, extracted from the blood plasma of people who already had immunity.... Should Christians accept these fractions in medical treatment? We cannot say. The Bible does not give details, so a Christian must make his own conscientious decision before God.
So if a JW tells you they were protected in this case by their blood policy, please tell them they were not.