It is a wrong quote. Science is supposed to keep changing as we find new information and discover that our previous theories were wrong.
A :-) Sickle cell disease occurs more often among people from parts of the world where malaria is or was common. It is believed that people who carry the sickle cell trait are less likely to have severe forms of malaria.
It would be AO and BO this would be the only one with a change of Type O blood the others do not have any chance
