Dear Sibagh,

It might seem strange, but a small piece of something dangerous can protect you against something much more dangerous. This idea has been around for a long time—and it works.

To learn more, I talked to Guy Palmer at Washington State University. As a scientist who studies infectious disease, Palmer likes learning about how to protect both human and animal health. Vaccines are one way to accomplish this.

Instead of making you sick, vaccines do something very powerful. They help your body learn more about a germ and how to protect you from it.

Dr. Universe, a grey cat with a lab coat, in a hero pose

Vaccines work by pushing a little piece of a virus or bacteria into your body. But they don’t give you the full germ that makes people sick. Instead, they give you a version that’s weak or dead. This germ can’t make copies of itself or spread in your body.

When your body meets the weak germ, it makes antibodies. Antibodies are like little warriors in your blood. They help you fight strong germs if you ever meet them in the future. This gives you a special kind of protection called immunity.

It’s no accident that the word “vaccine” comes from the Latin word “vaca,” meaning “cow.” The first vaccine was invented over 200 years ago, to protect against smallpox. It was created by pulling cowpox from a cow’s skin, then injecting it into a human.

Since then, scientists have invented more complicated ways of making vaccines. They can now safely work with viruses and bacteria in a lab, pulling out and changing pieces of them.

“All vaccines work essentially the same way,” Palmer explained. “The way they’re made is how they differ.”

Some vaccines use only parts of a germ, or a very weak version of it, so it can’t spread inside you. With other vaccines, the germs are killed by heating them up or using chemicals.

Vaccines help you build antibodies like a shield. But in order to make that shield, scientists have to figure out how different germs work. Some germs are more complicated than others, changing all the time. So we don’t have vaccines for everything yet.

“As time has gone on, we’ve gotten more sophisticated,” Palmer said. “We now can find the very piece of the organism that induces the immune response that protects us against disease. But the basic way vaccines work has stayed the same.”

It takes a long time to create a new vaccine. Scientists test them to make sure they are safe, and that can take several months to over a year. “First you have to test it to be sure it doesn’t cause disease in people—that it actually is safe, and there’s not something you weren’t expecting,” Palmer said.

It’s not very fun to get a shot. But remember: the sting is temporary, and the protection lasts. By getting vaccinated, you’re keeping yourself and everyone around you safe.

“We know through research that vaccines are safe,” Palmer said. “They protect us.”

Sincerely,
Dr. Universe