Humans build immunity with age, so infection is less common among adults than children.

After all, doesn't exposure to germs build immunity, and doesn't that help keep babies healthy in the long run?

Over the centuries, the Europeans had developed high degrees of immunity to these diseases, while the indigenous peoples had no time to build such immunity.

"I would never advocate giving a child a virus purposefully to build immunity," Frenck says.

He was trying to build immunity to pressure inside his son.

Minimizing the levels of insecticide applied is crucial because mosquitoes quickly build immunity, he said.

The wide-spectrum antibiotics worked to keep bacteria to a minimum while the body's own defense system [41] built immunity to the invaders.

When given to a healthy person, the vaccine triggers the immune system to respond and thus build immunity.

It takes two weeks to build immunity after being vaccinated.

How long does it take the body to build immunity after being vaccinated?