The honest answer is that immunotherapy works on a timeline that is different from most treatments families are used to, and setting the right expectation at the beginning is one of the most important things I do at the first immunotherapy consultation at Vatsalya Hospital, Varanasi. Most medications produce their effect quickly: an antihistamine reduces symptoms within an hour; an inhaler opens the airways within minutes. Immunotherapy is modifying the immune response at a fundamental level, and this biological change takes time. Most children begin to notice a meaningful reduction in their allergic symptoms during their first peak allergy season while on immunotherapy, which typically means somewhere between six and twelve months into treatment. This first noticeable improvement is often partial: symptoms that were severe become moderate, or the child begins to require their antihistamine or nasal spray less frequently rather than stopping it altogether. The immune changes continue to deepen as the treatment progresses. By the end of the second year, most children are showing a substantially more significant reduction in symptoms and medication requirements than they showed at the end of the first year. The full clinical benefit, and the sustained post-treatment benefit that is the defining feature of disease-modifying treatment, develops over the complete treatment course of three to five years. What I emphasise to families at Vatsalya Hospital is that the commitment to the full treatment duration is what delivers the lasting result. Stopping at eighteen months because the child feels significantly better is a very common pattern, and it is also the reason that many families report a gradual return of symptoms in the months after stopping early: the immune changes had not yet become durable. The benefit that persists for years after treatment is completed, which is what distinguishes immunotherapy from all other allergy treatments, requires the complete course to be achieved. The three-to-five-year commitment I ask of families is not arbitrary: it is the time the immune system needs to make a change that lasts, and every completed year of treatment is a step toward an outcome that medications alone cannot provide.
Written by Dr. Divyank Pathak, MBBS, MD (Paediatrics), IFPCCM, DPAA, FNPP, DPSM, FAAP, Director and Senior Consultant Paediatrician, Pediatric Critical Care and Allergy and Asthma Specialist, Vatsalya Superspeciality Children Hospital, Varanasi 221002. Phone: +91 9838713111.
