Not To Be Trusted With Knives

NaBloPoMo – Day 22 – mRNA Vaccines

November 22, 2020 by Beth

Way back in early January, when I set a goal to learn 20 new things in 2020, I didn’t anticipate things like “what’s it’s like to live through a pandemic” or “the importance of the toilet paper supply chain” would be on the list. But here we are.

On a happier and more science nerdery note, a new cool thing that I, along with everyone else in the world, is learning about is mRNA vaccines. Everyone1 is pretty excited with the recent news that Moderna and Pfizer/BioNTeach are reporting that their COVID-19 vaccines have been shown to be 95% effective in phase 3 clinical trials. Like all good scientists, I have to state that I’d like the data to be shared so that other scientists can do some peer-review (so far, only press releases have been released) and of course, it will be important to see what happens over time. 95% seems like too good to be true (50% effectiveness would have been acceptable and 75% would have been amazing, so 95% seems like unbelievably good). But for now, I’m choosing to be cautiously optimistic. Also, it got me curious to know more about mRNA vaccines, because they are different than traditional vaccines and there’s never actually been an mRNA vaccine approved for use before.

Typically, vaccines are made from small amounts of live virus, or an inactivated version of the virus. It’s injected into the body and your immune systems sees it and goes “hey, this is a foreign invader!” and then learns how to attack it. The idea is that you give either an inactivated version of the virus, so it can’t make you sick, or you give enough of the virus to mount that response, but not so much that you get sick. But once you’ve mounted that immune response, then when you encounter the real virus, your body goes “I know how to attack this!” and attacks the virus before it can make you sick.

But with an mRNA virus, you inject a piece of messenger RNA (mRNA), which is a type of molecule that the body uses when it make protein. It’s like a little instruction book that tells a cell how to make a specific protein. So say your body wants to make insulin or hemoglobin; it makes the mRNA with the instructions to make insulin or hemoglobin in it and then that goes off to another part of the cell that makes the protein. In the case of an mRNA virus, you inject a piece of mRNA with the code to make a protein and then your cells make that protein.

With the COVID-19 vaccine, the mRNA has the instructions to make the “spike protein”, which is the protein that sticks out on the surface of the coronavirus. So then your body makes the spike protein (but not the rest of the virus, so you can’t get sick from it) and your body sees that spike protein and goes “hey, this is a foreign invader!” and then learns how to attack it. Then when you encounter the real virus, your body goes “I know how to attack this!” and attacks the virus before it can make you sick.

One really important thing to note is that these vaccines need to be kept very cold – Moderna’s vaccine has to be shipped and stored at -20 degrees C (once thawed, it needs to be used within 30 days); Pfizer/BioNTech’s needs to be shipped and stored at -70 degrees C (once thawed, it needs to be used within 5 days). So a lot of logistics work needs to go into maintaining the cold chain from the point of manufacturing to the point of administration of the vaccines to people all around the world2

Anyway, I thought that was all pretty cool and its gives me flashbacks to my old Biochemistry days! Fingers crossed the these vaccines hold up as well under scrutiny – and time – as they are being advertised. And that the world figures out the supply chain issues, because apparently supply chain is more important thing in a pandemic than I ever would have thought it to be.

Coronavirus image: Posted on Flickr with a Creative Commons license.

Flickr with a Creative Commons license.

1. Well, everyone except conspiracy theorists that think vaccines are harmful and/or are a ploy to microchip us all, I suppose. [↩]
2. There are other vaccines, including non-mRNA ones) in phase 3 trials and some of them may turn out to be effective as well and not need to be kept so cold, so there will likely be a variety of things going on when it comes to getting vaccines to everyone. [↩]

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