Background: There is limited information regarding the impact of bronchial asthma and other underlying diseases on sequelae of COVID-19.

Aim: To clarify the impact of bronchial asthma as an underlying disease on post-COVID symptoms and pulmonary function.

Methods: We conducted an observational study with the Japanese Respiratory Society as secretariat, for post-COVID symptoms, chest CT imaging and pulmonary function tests for up to 12 mo in hospitalized moderate or severe COVID-19 patients (n=1069). In the present study, we examined asthma patients 3 months after discharge, in comparison with matched controls without asthma.

Results: There were 82 (7.7%) patients with asthma. More than half used ICS-containing medications (58.5%), and 6 were steroid-dependent. Ten (12.2%) had severe COVID-19 and 5 were treated with mechanical ventilation, those frequencies were not significantly different from those without asthma.  Asthma patients had significantly higher frequencies of dyspnea, cough, phlegm, fatigue, muscle weakness, sore throat, and tinnitus at 3 months, but no significant differences were found in the frequency of abnormal smell and/or taste, joint pain, headache, and ?brain fog? or sleep disturbance. There were also no significant differences in %predicted value of FVC(%FVC), %FEV1, %DLco, and %DLco/VA.

Conclusions: A significantly higher proportion of asthma patients had post-COVID symptoms at 3 months after discharge, but were not accompanied by pulmonary dysfunction. Limitations of this study include the fact that the data were up to delta strain, and future studies should consider the impact of mutations and current treatment on sequelae.