Body Defenses

The immune system spots viruses and attacks them. Vaccines train those defenses before a real infection, while medicines mostly make symptoms less severe.

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Age 14: open this week

In the picture

White blood cell: a rounded immune cell with a pale nucleus.
Y-shaped antibody: a small forked protein that sticks to a virus.
Virus particle: a round spiked particle.
Syringe: a clear tube with a needle and plunger.

Examples

A flu shot trains your body before flu season.
A cold medicine can lower a fever, but it does not kill the cold virus.

Key takeaways

Vaccines help the body respond faster to a virus.
Medicines for viral illness often reduce symptoms rather than remove the virus.

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