(单词翻译:单击)
How Vaccines Work
疫苗是如何发挥作用的
Vaccines are some of the best methods for preventing disease.
打疫苗是预防疾病最好的方法之一。
The reason vaccines are so effective is that they trigger the body's natural immune response to viruses.
疫苗之所以如此有效，是因为它们触发了人体对病毒的自然免疫反应。
When a person becomes infected with a new disease, their body recognizes that the virus is unfamiliar.
当一个人感染一种新的疾病时，他的身体会意识到这种病毒是陌生的。
The immune system then works to fight off the virus by producing antibodies.
然后，免疫系统就会产生抗体来击退病毒。
After recovering from a sickness, your body will remember how to fight it off if you are ever infected again.
从疾病中恢复后，你的身体会记住再次感染时的应对方式。
This provides a temporary immunity to the virus that you were exposed to.
这能够让你对接触到的病毒产生暂时的免疫力。
A vaccine works by imitating a real infection.
疫苗起效的方式是通过模拟真实的感染。
Most vaccines contain a weakened or inactive version of the virus they are meant to protect against.
大多数疫苗中都含有它们需要预防的病毒的弱化或灭活版本。
When this virus is injected into the body, the immune system believes it is harmful and attempts to fight it off.
当这种病毒被注射到体内时，免疫系统认为它是有害的，并尝试将其击退。
Because the immune system now recognizes this virus, it will remember how to produce antibodies if you are ever exposed to the real virus.
免疫系统通过这种方式认识这种病毒，因此在你接触到真正的病毒时，它会产生对应的抗体。
This way, you can be protected from disease without being infected first.
这样，你就可以不被病毒感染，免受疾病的侵袭。
