Epidemiologic and demographic characteristics
Of the 654 patients who were assessed for eligibility, 11 were excluded as their last injection date of SCIT was not recorded in the questionnaire. At V0, 249 patients (38.72%) were receiving SCIT on schedule while 394 patients (61.28%) were receiving postponed SCIT. At V1, 161 patients (25.04%) had already completed SCIT (for more than three years), and 163 patients (25.35%) had withdrawn from SCIT. Thus, a total of 105 patients treated on schedule (32.92%) and 214 patients with treatment delay (67.08%) were available for follow-up in V1. Of these, a few patients were excluded due to missing data or inappropriately filled in questionnaires (Figure 1 ).
The median time interval of delayed SCIT was 7 weeks, and ranged from 1 to 30 weeks. The groups of scheduled SCIT and delayed SCIT were comparable in terms of the treatment phases and diagnosis. There was no significant difference for age, gender, and adverse reactions between the scheduled SCIT and delayed SCIT groups at both V0 and V1. None of the study patients were infected by COVID-19 during the study (Table 1 ).