ELI5: What is the difference between mRNA and traditional vaccines

An mRNA vaccine is like giving your body a recipe to make a tiny piece of a virus, while a traditional vaccine is like showing your body the whole virus (but weakened or dead) so it can learn to fight it.

Imagine you want to teach your body to recognize a robber.

• Traditional Vaccine: It's like showing your body a picture of the robber. The robber is wearing a mask and is tied up, so they can't hurt you, but your body can still see what they look like. Your body then learns to recognize that robber if it ever sees them again, even if the robber isn't tied up anymore. These vaccines use weakened or dead versions of the real virus to trigger an immune response.

• mRNA Vaccine: Instead of showing a picture of the whole robber, you give your body a recipe to make just the robber's mask. Your body follows the recipe and makes the mask. Then, your body sees the mask and learns to recognize it. It doesn't matter if the robber is wearing the mask or not; your body will know it's the robber. The mRNA tells your cells to make a harmless piece of the virus (like the mask), and your body learns to fight that piece, giving you protection against the real virus.

mRNA vaccines are faster to make because you only need the recipe (the mRNA), not the whole virus.