Just What Is An RNA Vaccine Anyway?

And might its never-done-before nature make it a harder sell?

Yes, everyone’s getting hyped-up all of a sudden as Massachusetts-based biotech company Moderna, said people it tested after it gave them two doses of the messenger RNA vaccine its developing, showed they were able to stimulate an immune response to COVID-19 without actually getting sick. Especially the stock market, which had one of its biggest single day rallies in weeks. (And Moderna’s leveraging that action by immediately announcing plans to raise more than $1-billion by selling more shares of its stock.) 

And this all may be something to get very excited about, even though at this point it’s based on a sampling of 8 people. If subsequent trials go well, that’s great news. Pretty damn close to a miracle.

Moderna’s vaccine — and at least one other that is being developed and tested — is built on something that’s never been done before with vaccines. So there’s no real data on how safe it is for humans as time goes by. And there won’t be. At least not by the fall, when masses of people could be getting injected with it, if the vaccine works as hoped. In that case, even though this type of vaccine has never been used in humans before, there won’t be years of trials behind it to figure out whether it’s totally safe, because there can’t be. Now, already there are some long-running clinical trials for RNA vaccines aimed at certain types of cancer, so there might be some safety data that can be culled from those studies, although none of those vaccines is actually officially in use yet.

Will most people take an RNA vaccine for COVID-19 anyway if it’s shown in trials to protect effectively against the virus, and let them get fully back to their lives? Yes. Is it likely not to have horrible long term effects on people? For reasons we’ll explain in a sec, probably.

Right now, most every vaccine humans get is made up of a dead or weakened form of a virus or disease you’re being vaccinated against, giving your body the ability to manufacture antibodies against the disease without you getting very sick. RNA-based vaccines, like the one we’re talking about, don’t work that way at all.

With RNA, instead of giving you enough of the “bad stuff” to stimulate you to produce antibodies without making you sick, you get injected with a bit of genetic code that’ll get you to make something resembling the “bad stuff” yourself, and then make the stuff that’ll snuff that “bad stuff” out.

Here’s a little illustration of the way it works from a very informative Harvard University science blog:

So with an RNA vaccine, you actually get injected with genetic material, which your cells then use to create an antigen, which your immune system then creates antibodies against. Instead of a normal vaccine where you get injected directly with the antigen.

So is that more safe than a conventional vaccine? Less safe? The same?

The Harvard blog likens an RNA vaccine to providing a chef (your body) with a recipe (the RNA code). The “ingredients” are in your body already. The vaccine just tells your body how to make it. And then you, the “chef” takes over and whips it up. Following that analogy along, the Harvard piece asserts that means it’s very likely safe because:

Injection of RNA presents no risk of disrupting the cell’s natural DNA sequence. To continue our kitchen analogy, disruption from DNA is like inserting a foreign ingredient in an existing recipe, which can change the resulting dish.  Injecting RNA, on the other hand, is like temporarily adding a new recipe in the cook book while keeping old ones untouched, and therefore will not result in surprising changes to existing recipes.”


We can see how it’s easy to feel this is how many sci-fi/end-of-the-world/zombie movies start.

At the same time, we’d be willing to take the shot if someone we respect tells us it’s very, very likely safe. So at the very least it’ll mean education about the product and endorsements from voices Americans (and people around the world) trust, may become almost as important as its effectiveness (if it is proven to be effective).

And there are plenty of noisy anti-vaxxers in the U.S. And a lot of people who trust the government less and less. Now add to that conspiracy theorists about the origins of COVID-19 (which seem to include the President himself, and certainly his Secretary of State). Now add to that a type of vaccine that’s so new, it’s never been used in humans before. Now add to that many people’s natural tendencies to be afraid of the new. And maybe that all adds up to a problem.

You’ve also got a huge potential irony: President Trump, even though he’s historically leaned heavily toward the anti-vax, rightly sees quick development of any kind of effective vaccine against COVID-19 as something that’ll make him a hero. (Whereas we’d imagine if there was a different President, and Trump was just a private citizen, he’d be skeptic #1.) But that’s fine: as we’ve said many times, we’re rooting for the President in this regard.

One last question today: what happens if the vaccine that ends up being the most effective is developed in China? Since the virus started there, researchers there have had a head start. Interestingly, they’re focusing primarily on “old-fashioned” vaccines, where people are injected with inactivated virus and develop an immune response that way. So that’s the type of vaccine most Americans are most used to getting. But would they take it if it came from China? Or would Americans even have immediate access to it, as we’ve come to expect with everything?

A sampling of various COVID-19 vaccines under development