十万个为什么·科学启蒙30篇（2）
10 / 30
正在校验访问权限...
How Do Vaccines Train Your Immune System?
疫苗是如何训练免疫系统的？
-
Vaccines introduce harmless versions of pathogens — such as dead viruses, weakened live ones, or just key protein fragments — to safely mimic infection.
-
Specialized immune cells called dendritic cells recognize these foreign markers and activate T-cells and B-cells to mount a targeted response.
-
B-cells produce antibodies that latch onto specific antigens, while memory cells remain in the body for years — ready to respond faster if the real pathogen returns.
-
Some vaccines require booster shots because immunity fades over time or because the pathogen mutates rapidly, like influenza viruses.
-
mRNA vaccines work differently: they deliver genetic instructions so your own cells temporarily make harmless spike proteins, triggering immunity without using any virus.
-
Herd immunity occurs when enough people are vaccinated, making it hard for diseases to spread — protecting those who can’t be vaccinated for medical reasons.
-
Before vaccines, measles killed over 2.6 million people annually worldwide; today, vaccination prevents an estimated 4–5 million deaths each year.
-
Side effects like sore arms or mild fever are normal signs that your immune system is learning — not evidence the vaccine is dangerous.