Effects of allergen extract exchange in children and adolescents receiving house dust mite allergen immunotherapy during the Covid-19 pandemic: Real-life data

ABSTRACT

Background: In our country, allergen extracts (AEs) for house-dust mite (HDM) allergen immunotherapy (AIT), were provided by two companies which are Novohelisen Depot and Alutard SQ. During the Covid-19 pandemics, Novohelisen DepotHDM allergens could not be imported due to the unforeseen reasons. In order to ensure the continuity of AIT, consent obtained patients were treated with the AE of the other company. In this study, it was aimed to determine the frequencies of local and systemic side effects (SEs), clinical response, and the effect of AE change on these parameters during the Covid-19 pandemics. Method(s) 59 patients aged >= 5 years, followed up with the diagnosis of allergic rhinoconjunctivitis (ARC) and/or allergic asthma, and clinically related HDM allergy were included in the study. Demographic data of the patients and SEs during the treatment were recorded from the onset of subcutaneous AIT (SCIT) until September 2021. A transition protocol was created in order to maintain maximum effectiveness and minimize potential SEs of AIT after AE switching. After thetransition protocol, the frequency of SEs, and symptoms and medication scores were recorded during each AIT visit. Result(s) Of 59 patients, 38 (64.4%) were male, 27 (45.7%) had ARC and 32 (54.2%) had both allergic asthma and ARC. Age at the onset of AIT was 12 (6-17) years, and duration of the treatment was 30 (8-48) months. In this study 29 patients received Alutard-SQ (group 1) and 30 patients, Novohelisen-Depot (group 2). 19 patients in group 2 switched to AE of Alutard SQ. During the treatment period, 1209 Novohelisen Depot and 1504 Alutard SQ injections were administered and a total of 140 (5.2%) local reactions (LRs), 50 (1.8%) large local reactions (LLRs), and 7 (0.25%) systemic reactions (SRs) were observed. In group 2, 61 (8.3%) LRs and 1 (0.13%) SR were observed before switching, 5 (1.4%) LRs and neither LLR nor SR were observed after switching. Adherence to SCIT has been increased from 49.1% to 79.6% and the decrease in symptom and medication scores in the pre-transition period continued after switching. Conclusion(s) During the Covid-19 pandemics, HDM AEs transition protocol was safe in terms of local and systemic side effects, and AIT was effective.