I'll start by saying I'm not a doctor. This is my layman's understanding.

Historically, vaccines have been samples of either weakened or dead viruses. Through trial and error, we've been able to determine how to weaken or kill these viruses, then inject them into ourselves in the hopes that our immune system can learn to recognize and kill the virus. This has worked really well for a long time, but it's costly and can be difficult to scale. For example, horses have very strong immune systems. It's quite common to inject a virus that hurts humans into a horse, then harvest the horse's blood to acquire the material needed to produce a vaccine. The horse's immune system learns how to kill the virus, and we can use the to teach our immune systems.

mRNA vaccines take a whole different approach. They kind of co-opt the mechanism that viruses use to replicate.

First, let's tall about what RNA is. You might know that DNA is used to produce proteins, and proteins are the tools that life uses to do... stuff. Almost everything, really. Thing is, DNA is stored safely inside cells' nuclei, but protein production happens outside the nuclei, in ribosomes. So if DNA is needed to produce proteins, but DNA can't be moved to the protein production center, how do? Our cells can produce another molecule called RNA. It's basically half of DNA. Since you can derive one half of DNA from the other, it essentially carries the same information. Inside the nuclei, RNA is produced based on your DNA. That RNA is then moved to the protein production center to be used as the blueprint for protein production. Voila! Your cells have proteins now and can do stuff.

What did that have to do with viruses? But first, how do viruses work? Funny thing: at their core, viruses are kind of like protein missiles with an RNA payload. (This is why people argue that viruses aren't really alive.) Viruses pierce your cells and inject their RNA into your cells. That RNA provides the blueprints to produce more RNA and the protein module, effectively, a copy of the virus. The viruses uses your cells' infrastructure to reproduce.

With me so far? Here's where it gets cool.

What if we could capture a virus' RNA? What if we could then isolate just enough of the RNA blueprint to get some part of the protein missile, without the payload? And then what if we could get so specific that we could make sure that part of the protein missile is something your immune system could learn to recognize and kill? Lastly, what if we could package this harmless but recognizable part of the virus in a manner that your cells could mass manufacture it?

This is mRNA, the "m" standing for "messenger." mRNA vaccines basically give your cells the blueprint to produce a recognizable part of a virus that won't hurt you. Your cells then produce that virus part, and your immune system learns how to recognize and kill the virus based on that part.

The best part? We can do this fast. No need for trial and error on how to weaken viruses. No need to manage livestock like horses specifically to harvest their immune system material. The COVID vaccine was an mRNA vaccine. I haven't actually checked the numbers, but I'm very confident that the COVID vaccine R&D was the fastest humanity has ever had for any vaccine. We'd been researching and experimenting with mRNA vaccines already, but they weren't yet approved for medical use. For good reason, medicines go through a huge amount of testing before we start injecting ourselves with magic feel-good juice. Given the emergency that COVID was, most countries fast-tracked their approval process for the COVID mRNA vaccine. In the long run, this may actually have been a benefit, as we've learned a lot about how to produce these types of vaccines rapidly, at scale and even update them for new variants of a virus.

So yeah, mRNA vaccines are super fucking cool. They're also a remarkably clever innovation, copying an idea from viruses and adapting it to a way to kill viruses. Theoretically, future vaccines should be produced faster, be better targeted, and have fewer side effects.

Thanks for coming to my TED talk? 😅