[Clinical characteristics of children infected with SARS-CoV-2 Omicron variant combined with allergic disease]

Objective: To investigate the clinical characteristics of children with allergic diseases suffering from SARS-CoV-2 Omicron variant strains. Methods: This was a cross-sectional study. A total of 43 pediatric patients with allergic diseases infected by SARS-CoV-2 from April 25, 2022 to June 8, 2022 in Shanghai Jiao Tong University School of Medicine were selected as the allergic disease group, while 114 cases without underlying diseases and 16 cases with other underlying diseases were selected as control groups diagnosed at the same period. Clinical data including clinical features, laboratory tests, duration of hospitalization, and the time to negative turn of novel coronavirus nucleic acid were collected and analysed. Kruskal-Wallis H test, chi-square test or Fisher exact test were used for comparison among three groups. Results: Among the 43 patients with allergic diseases, 28 were males and 15 were females, with an age of 4.4 (2.1, 8.2) years on admission, including 32 mild cases and 11 common cases. The allergic disease group included 20 cases (46.5%) of atopic dermatitis and eczema, followed by 14 cases (32.6%) of rhinitis, 8 cases (18.6%) of food allergies, 7 cases (16.3%) of asthma, 4 cases (9.3%) of allergic conjunctivitis and 2 cases (4.7%) of drug allergy. Among the 114 cases without underlying diseases, 57 were males and 57 were females, with an age of 2.8 (1.2, 5.6) years on admission, including 93 mild cases and 21 common cases. Among the 16 cases with other underlying diseases, 9 were males and 7 were females, with an age of 3.0 (2.6, 10.8) years on admission, including 13 cases mild and 3 cases common cases. Children with allergic diseases had higher frequency of sore throat and vomiting than those without underlying diseases (10 cases (23.3%) vs.9 cases (7.9%), 14 cases (32.6%) vs. 11 cases (9.6%), χ²=6.93, 12.24, both P<0.05). The lymphocyte count of patients with allergic disease was lower than those without underlying disease (1.1 (0.7,1.7)×10⁹ vs. 1.6 (1.1,2.7)×10⁹/L, H=-28.00,P=0.005). There were no significant differences in age, gender, typing of SARS-CoV-2, the duration of hospitalization, cycle threshold values of SARS-CoV-2 and the time to negative turn of novel coronavirus nucleic acid among the three groups (all P>0.05). Conclusions: Children with allergic diseases may suffer from sore throat and vomiting more frequently when infected with SARS-CoV-2 Omicron variant. The combination of allergic diseases hardly influenced the disease course of SARS-CoV-2 in children.