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Understanding herd immunity

Good for you—and the greater good too!

When you get a vaccine, you're not just protecting yourself from disease. You're helping safeguard your family, friends and others.

It's a concept called "herd immunity" or "community immunity." Here's a quick look at how it works.

A BUG GETS BUSY

Let's say nasty germs enter a community where only a few people are immunized against the disease. The germs spread quickly. Since so many people aren't protected, many people can end up getting sick.

IT TAKES A HERD

Now, let's consider a healthier situation. Herd immunity occurs when enough people are vaccinated that it's difficult for germs to spread. Those who are vaccinated have immune systems that detect and fight off the bug. Very few people get sick-and there are fewer germs to infect others in the community.

THOSE WHO NEED THE HERD MOST

Herd immunity is vital, because not everyone can get vaccinated. Some people-like infants, pregnant women and people with weak immune systems-can't receive certain vaccines. But if most of the people around them are vaccinated, they'll be better protected against germs that try to infect the community.

A CLASS ACT

When it comes to being safe and effective, vaccines have an impressive record, saving countless lives. They remain the best way to protect yourself and others from many contagious and serious diseases.

A SAFER PLACE FOR ALL

Here's just one example of herd immunity at work: In the mid-1960s, a rubella epidemic broke out. More than 12 million Americans were infected. It killed 2,000 babies and caused 11,000 miscarriages. Then, in 1969, the rubella vaccination program was introduced. Rubella was eliminated in the U.S. in 2004, according to the Centers for Disease Control and Prevention. More recent cases have been in people who lived or traveled outside the states.

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