I would consider this an example of a safe exposure to allow the immune system to exercise, rather than a serious disease, unless the plan is to literally to make children grow up sickly and malnourished.
Children who grow up with serious diseases (i.e., diseases that cause them serious health problems) are weakened for the rest of their lives, which leaves them more vulnerable to illness later.
That is not the goal of this therapy. They will keep the parasite population in check (e.g., by using parasites that cannot reproduce on their own) to ensure that the patient's health is improved by the treatment, not worsened by it.
Children who grow up with serious diseases (i.e., diseases that cause them serious health problems) are weakened for the rest of their lives, which leaves them more vulnerable to illness later.
That is not the goal of this therapy. They will keep the parasite population in check (e.g., by using parasites that cannot reproduce on their own) to ensure that the patient's health is improved by the treatment, not worsened by it.