mRNA Vaccines — Building from a Message (Part 1)

To understand this, you need to know a little about how your body already fights disease.

Deep inside every cell is your DNA.

Think of it as an enormous cookbook holding the recipe for everything your body can build, from the proteins in your muscles, to the hormones that travel through your blood, to the defenses that fight off disease.

But the cookbook never leaves the cell.

So when the cell needs to build something, it copies just the one recipe it needs onto a short working copy, made fresh whenever it's needed.

That copy is called RNA.

The kind that matters for our story is called messenger RNA, or mRNA.

Name tells you exactly what it does.

It is a messenger carrying a single recipe from the cookbook to the place where it actually gets built.

Your body send out these messengers constantly telling your cells to build this, make that.

One of the things your body builds this way is its defense against germs.

When a germ invades, your body needs to build something specific to fight it, a protein called an antibody, shaped to match that exact germ.

A different germ needs a different antibody built from a different recipe.

So the cell pulls the matching recipe, sends out the messenger, and builds the antibody it needs, and remembers that recipe so it's ready even faster the next time.

Now, here is the thought that changed everything.

If mRNA is just a messenger carrying a recipe, what if we could write our own? Think what that means for a vaccine.

You write the message with the recipe for one small harmless piece of a germ and send it in.

These cells read it and build that piece.

The immune system finds it and builds the antibody to match exactly as if the real germs were there.

So when the real germ arrives, the body is already armed.

You never bring in the germ.

You just send the recipe, and the message is far easier thing to make than a living virus.

It was beautiful.

It was simple, but in practice it did not work because when scientists actually tried it, the body fought back.