Table 1.

Mechanisms of severe respiratory syncytial virus (RSV) infection in the rare diseases targeted in this study

Disease group	Mechanism for severe RSV infection
	Reduced ventilation competencea	Difficulty in expectorationb
Pulmonary hypoplasia		○
Airway stenosis	○	○
Congenital esophageal atresia	Δ	○
Inherited metabolic disease	○
Neuromuscular disease		○

○ = Yes, Δ = Yes, depending on the condition, Blank = not applicable

^aReduced ventilation competence: Because of their reduced ventilation competence, children with airway stenosis who develop RSV-induced lower respiratory tract infection may experience hypoxia

^bDifficulty in expectoration: Because of the difficulty in expectoration, patients cannot eliminate RSV via the sputum, which results in prolonged infection. Secretions retaining in the respiratory tract make ventilation difficult