Dear Dore,
Has the baby been transfused? At five months the baby probably has not had more than a couple of transfusions. The ferritin level may not be a reflection of the baby's iron levels - rather it may be a response to infection, cold or flu. I don't think that the baby would need desferal at this time - commonly desferal is introduced closer to 18months - 2yrs of age. The baby's ferritin should be measured again at a later time, my guess is that it should be much lower at that time, unless if there is another underlying condition causing the iron levels to be higher (such as hyperchromotosis).
Ferritin is a value measured over time to get a general idea of iron levels, so no action should be taken based on a single ferritin vallue.
Best of luck for the little one,
Sharmin