This disease has only affected around 100 people in the world, but their average survival span was around 18 months.

世界上只有大约100个人患有这种疾病，但是他们的平均寿命是18个月。

Various interventions, such as infection-fighting drugs, can increase a population's average survival time, but only approaches that slow the body's rate of aging will increase the maximum lifespan.

有很多种外在作用（如注射抗感染药物）都可以提高人群的平 均生存时间，但是只有能够降低人体衰老速度的方式才能够提高最大寿命值。