保护期至少持续20年，应为终身免疫。

Protection lasts at least 20 years and should be lifelong.

youdao

自然经过的麻疹，一般产生终身免疫。

An unmodified attack of measles usually confers lifelong immunity.

youdao

人们认为一旦感染一次感冒就能终身免疫，这是错误的。

People think that once you get infected one time you develop immunity for the rest of your life. This is wrong.

youdao