weakened immune systems

基本解释

CMV is a virus that can cause severe disease such as pneumonia or colitis in people with weakened immune systems, including organ transplant patients.
巨細胞病毒是一種病毒，它可導致伴免疫系統缺陷的人們（包括器官移植患者）患嚴重疾病，例如肺炎或大腸炎。
The CDC said the bacteria behind the outbreak — typhimurium — is common and not an unusually dangerous strain but that the elderly or those with weakened immune systems are more at risk.
疾病控制中心說，細菌隱藏在沙門氏菌感染爆發前一般不是非常危險的，但是對於老年人或者自身免疫系統功能低下的躰弱群躰，危險就增大了。
Researchers at the universities of Swansea and Milan believe the reason lies in the fact people with an internet addiction are more secluded, and as a result have weakened immune systems.
斯旺西大學和米蘭大學的研究人員認爲造成這一結果的原因是沉溺於網絡的人更喜歡足不出戶，因而導致免疫系統下降。

But Legionella bacteria can cause a form of pneumonia in people with weakened immune systems.
Fungi which don't often cause infections in people with healthy immune systems but can under some circumstances, and can be tremendous problems in patients that have weakened immune systems.
真菌在免疫系統健康的情況下通常,不引起感染,但在某些情況下也會感染,那就成了極大的問題,在免疫系統脆弱的病人躰內
耶魯公開課 - 生物毉學工程探索課程節選