Background: 3‐year subcutaneous specific immunotherapy (SIT) in children with seasonal allergic rhinoconjunctivitis reduced the risk of developing asthma during treatment and 2 years after discontinuation of SIT (5‐year follow‐up) indicating long‐term preventive effect of SIT.
Objective: We evaluated the long‐term clinical effect and the preventive effect of developing asthma 7‐years after termination of SIT.
Methods: One hundred and forty‐seven subjects, aged 16–25 years with grass and/or birch pollen allergy was investigated 10 years after initiation of a 3‐year course of SIT with standardized allergen extracts of grass and/or birch or no SIT respectively. Conjunctival provocations were performed outside the season and methacholine bronchial provocations were performed during the season and winter. Asthma was assessed by clinical evaluation.
Results: The significant improvements in rhinoconjunctivitis and conjunctival sensitivity persisted at the 10‐year follow‐up. Significantly less actively treated subjects had developed asthma at 10‐year follow‐up as evaluated by clinical symptoms [odds ratio 2.5 (1.1–5.9)]. Patients who developed asthma among controls were 24/53 and in the SIT group 16/64. The longitudinal treatment effect when adjusted for bronchial hyper‐responsiveness and asthma status at baseline including all observations at 3, 5 and 10 years follow‐up (children with or without asthma at baseline, n = 189; 511 observations) was statistically significant (P = 0.0075). The odds ratio for no‐asthma was 4.6 95% CI (1.5–13.7) in favor of SIT.
Conclusion: A 3‐year course of SIT with standardized allergen extracts has shown long‐term clinical effects and the potential of preventing development of asthma in children with allergic rhinoconjunctivitis up to 7 years after treatment.
Clinical implication: Specific immunotherapy has long‐term clinical effects and the potential of preventing development of asthma in children with allergic rhino conjunctivitis up to 7 years after treatment termination.
