In the old days when they took you platelets or plasma out of you blood at a blood bank they take it out of one arm and reintroduce in the other arm. .
in the old days, they used the same damn syringe for vaccinations for loggers. My Great granfather died of HEP. C at the age of 25. His wife (my GGMA) died from lung cancer years later, because "A DOCTOR" prescribed a cigarette and a cup of coffee, for her nerves.( because of her husbands death)
so doctors in the old days even in the 80's didnt know much more than the 30's.
case/point AIDS and HEP C in blood banks.
thats why they call medicine a practice not a perfect.
but i would listen in this case, they still know more than me.
Remember a bonefied Doctor still is a far cry from some Medical Assistant off the street that took some night courses, that takes and gives you blood on the poor side of town.