Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis and pneumonia among infants and children under one year of age.It also causes severe respiratory illness in the elderly.

• RSV是婴儿和小于一岁的儿童的细支气管炎以及肺炎的最常见的原因.；它在上了年纪的人中还会引起严重的呼吸道疾病