Efficacy and safety of Artemisia annua sublingual immunotherapy in patients with seasonal allergic rhinoconjunctivitis over two pollen seasons

Objective This study investigates the efficacy and safety of sublingual immunotherapy (SLIT) with A. annua allergens in patients with seasonal allergic rhinoconjunctivitis over two pollen seasons. Methods Seventy patients with moderate-severe seasonal allergic rhinoconjunctivitis were divided evenly into the SLIT and control groups. The SLIT last from 3 months before the summer-autumn pollen season in 2021 till the end of the summer-autumn pollen season in 2022. The daily individual symptom score, total rhinoconjunctivitis symptom score (dTRSS), total medication score (dTMS), combined score of medication and rhinoconjunctivitis symptom (dCSMRS), visual analog scale (VAS) score, and adverse events (AEs) were evaluated. Results The average pollen concentration in 2022 was twice that previous two-year during the pollen season. Fifty-six patients completed treatments (SLIT group: 29, control group: 27). Compared with baseline, the individual symptoms, dTRSS, dTMS, dCSMRS, and VAS scores of SLIT group declined in 2021. After 16 months of SLIT, all efficacy indexes in 2022 were still lower than baseline and equivalent to those in 2021. In control group, the efficacy indexes in 2022 were higher than that in 2020 and 2021. The efficacy indexes of SLIT group were lower than those of control group in 2021 and 2022. SLIT is effective for both mono- and poly-sensitized patients. AEs incidence in SLIT group was 82.7% without severe AEs. Conclusions The A. annua -SLIT can obtain efficacy and safety over two pollen seasons for patients with moderate-severe seasonal allergic rhinoconjunctivitis.