They found that all babies in the study were at increased risk if they had bronchiolitis, a lung infection usually caused by respiratory syncytial virus or RSV.

• 他们发现研究中的所有婴儿，如果患了小儿毛细支气管炎，是一种肺部感染，通常是由于呼吸道合胞病毒感染RSV，患哮喘的机率也升高。